Async optimization

AMWD.Protocols.Modbus.Common/Contracts/ModbusClientBase.cs

@@ -10,19 +10,27 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 	/// <summary>
 	/// Base implementation of a Modbus client.
 	/// </summary>
-	public abstract class ModbusClientBase : IDisposable
+	/// <remarks>
+	/// Initializes a new instance of the <see cref="ModbusClientBase"/> class with a specific <see cref="IModbusConnection"/>.
+	/// </remarks>
+	/// <param name="connection">The <see cref="IModbusConnection"/> responsible for invoking the requests.</param>
+	/// <param name="disposeConnection">
+	/// <see langword="true"/> if the connection should be disposed of by Dispose(),
+	/// <see langword="false"/> otherwise if you inted to reuse the connection.
+	/// </param>
+	public abstract class ModbusClientBase(IModbusConnection connection, bool disposeConnection) : IDisposable
 	{
 		private bool _isDisposed;
 
 		/// <summary>
 		/// Gets or sets a value indicating whether the connection should be disposed of by <see cref="Dispose()"/>.
 		/// </summary>
-		protected readonly bool disposeConnection;
+		protected readonly bool disposeConnection = disposeConnection;
 
 		/// <summary>
 		/// Gets or sets the <see cref="IModbusConnection"/> responsible for invoking the requests.
 		/// </summary>
-		protected readonly IModbusConnection connection;
+		protected readonly IModbusConnection connection = connection ?? throw new ArgumentNullException(nameof(connection));
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="ModbusClientBase"/> class with a specific <see cref="IModbusConnection"/>.
@@ -32,20 +40,6 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			: this(connection, true)
 		{ }
 
-		/// <summary>
-		/// Initializes a new instance of the <see cref="ModbusClientBase"/> class with a specific <see cref="IModbusConnection"/>.
-		/// </summary>
-		/// <param name="connection">The <see cref="IModbusConnection"/> responsible for invoking the requests.</param>
-		/// <param name="disposeConnection">
-		/// <see langword="true"/> if the connection should be disposed of by Dispose(),
-		/// <see langword="false"/> otherwise if you inted to reuse the connection.
-		/// </param>
-		public ModbusClientBase(IModbusConnection connection, bool disposeConnection)
-		{
-			this.connection = connection ?? throw new ArgumentNullException(nameof(connection));
-			this.disposeConnection = disposeConnection;
-		}
-
 		/// <summary>
 		/// Gets or sets the protocol type to use.
 		/// </summary>
@@ -67,7 +61,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeReadCoils(unitId, startAddress, count);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			// The protocol processes complete bytes from the response.
@@ -92,7 +86,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeReadDiscreteInputs(unitId, startAddress, count);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			// The protocol processes complete bytes from the response.
@@ -117,7 +111,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeReadHoldingRegisters(unitId, startAddress, count);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			var holdingRegisters = Protocol.DeserializeReadHoldingRegisters(response).ToList();
@@ -140,7 +134,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeReadInputRegisters(unitId, startAddress, count);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			var inputRegisters = Protocol.DeserializeReadInputRegisters(response).ToList();
@@ -184,7 +178,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			do
 			{
 				var request = Protocol.SerializeReadDeviceIdentification(unitId, category, requestObjectId);
-				var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+				var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				Protocol.ValidateResponse(request, response);
 
 				result = Protocol.DeserializeReadDeviceIdentification(response);
@@ -247,7 +241,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeWriteSingleCoil(unitId, coil);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			var result = Protocol.DeserializeWriteSingleCoil(response);
@@ -268,7 +262,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeWriteSingleHoldingRegister(unitId, register);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			var result = Protocol.DeserializeWriteSingleHoldingRegister(response);
@@ -289,7 +283,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeWriteMultipleCoils(unitId, coils);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			var (firstAddress, count) = Protocol.DeserializeWriteMultipleCoils(response);
@@ -309,7 +303,7 @@ namespace AMWD.Protocols.Modbus.Common.Contracts
 			Assertions();
 
 			var request = Protocol.SerializeWriteMultipleHoldingRegisters(unitId, registers);
-			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken);
+			var response = await connection.InvokeAsync(request, Protocol.CheckResponseComplete, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 			Protocol.ValidateResponse(request, response);
 
 			var (firstAddress, count) = Protocol.DeserializeWriteMultipleHoldingRegisters(response);

AMWD.Protocols.Modbus.Serial/ModbusRtuProxy.cs

@@ -192,17 +192,16 @@ namespace AMWD.Protocols.Modbus.Serial
 		public Task StopAsync(CancellationToken cancellationToken = default)
 		{
 			Assertions();
-			return StopAsyncInternal(cancellationToken);
+			StopAsyncInternal();
+			return Task.CompletedTask;
 		}
 
-		private Task StopAsyncInternal(CancellationToken cancellationToken)
+		private void StopAsyncInternal()
 		{
 			_stopCts?.Cancel();
 
 			_serialPort.Close();
 			_serialPort.DataReceived -= OnDataReceived;
-
-			return Task.CompletedTask;
 		}
 
 		/// <summary>
@@ -215,7 +214,7 @@ namespace AMWD.Protocols.Modbus.Serial
 
 			_isDisposed = true;
 
-			StopAsyncInternal(CancellationToken.None).Wait();
+			StopAsyncInternal();
 
 			_serialPort.Dispose();
 			_stopCts?.Dispose();
@@ -332,7 +331,7 @@ namespace AMWD.Protocols.Modbus.Serial
 			responseBytes.AddRange(requestBytes.Take(2));
 			try
 			{
-				var coils = await Client.ReadCoilsAsync(unitId, firstAddress, count, cancellationToken);
+				var coils = await Client.ReadCoilsAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[(int)Math.Ceiling(coils.Count / 8.0)];
 				for (int i = 0; i < coils.Count; i++)
@@ -371,7 +370,7 @@ namespace AMWD.Protocols.Modbus.Serial
 			responseBytes.AddRange(requestBytes.Take(2));
 			try
 			{
-				var discreteInputs = await Client.ReadDiscreteInputsAsync(unitId, firstAddress, count, cancellationToken);
+				var discreteInputs = await Client.ReadDiscreteInputsAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[(int)Math.Ceiling(discreteInputs.Count / 8.0)];
 				for (int i = 0; i < discreteInputs.Count; i++)
@@ -410,7 +409,7 @@ namespace AMWD.Protocols.Modbus.Serial
 			responseBytes.AddRange(requestBytes.Take(2));
 			try
 			{
-				var holdingRegisters = await Client.ReadHoldingRegistersAsync(unitId, firstAddress, count, cancellationToken);
+				var holdingRegisters = await Client.ReadHoldingRegistersAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[holdingRegisters.Count * 2];
 				for (int i = 0; i < holdingRegisters.Count; i++)
@@ -444,7 +443,7 @@ namespace AMWD.Protocols.Modbus.Serial
 			responseBytes.AddRange(requestBytes.Take(2));
 			try
 			{
-				var inputRegisters = await Client.ReadInputRegistersAsync(unitId, firstAddress, count, cancellationToken);
+				var inputRegisters = await Client.ReadInputRegistersAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[count * 2];
 				for (int i = 0; i < count; i++)
@@ -492,7 +491,7 @@ namespace AMWD.Protocols.Modbus.Serial
 					LowByte = requestBytes[5],
 				};
 
-				bool isSuccess = await Client.WriteSingleCoilAsync(requestBytes[0], coil, cancellationToken);
+				bool isSuccess = await Client.WriteSingleCoilAsync(requestBytes[0], coil, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -531,7 +530,7 @@ namespace AMWD.Protocols.Modbus.Serial
 					LowByte = requestBytes[5]
 				};
 
-				bool isSuccess = await Client.WriteSingleHoldingRegisterAsync(requestBytes[0], register, cancellationToken);
+				bool isSuccess = await Client.WriteSingleHoldingRegisterAsync(requestBytes[0], register, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -591,7 +590,7 @@ namespace AMWD.Protocols.Modbus.Serial
 					});
 				}
 
-				bool isSuccess = await Client.WriteMultipleCoilsAsync(requestBytes[0], coils, cancellationToken);
+				bool isSuccess = await Client.WriteMultipleCoilsAsync(requestBytes[0], coils, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -648,7 +647,7 @@ namespace AMWD.Protocols.Modbus.Serial
 					});
 				}
 
-				bool isSuccess = await Client.WriteMultipleHoldingRegistersAsync(requestBytes[0], list, cancellationToken);
+				bool isSuccess = await Client.WriteMultipleHoldingRegistersAsync(requestBytes[0], list, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -705,7 +704,7 @@ namespace AMWD.Protocols.Modbus.Serial
 
 			try
 			{
-				var deviceInfo = await Client.ReadDeviceIdentificationAsync(requestBytes[0], category, firstObject, cancellationToken);
+				var deviceInfo = await Client.ReadDeviceIdentificationAsync(requestBytes[0], category, firstObject, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				var bodyBytes = new List<byte>();
 
@@ -855,5 +854,21 @@ namespace AMWD.Protocols.Modbus.Serial
 		}
 
 		#endregion Request Handling
+
+		/// <inheritdoc/>
+		public override string ToString()
+		{
+			var sb = new StringBuilder();
+
+			sb.AppendLine($"RTU Proxy");
+			sb.AppendLine($"  {nameof(PortName)}:   {PortName}");
+			sb.AppendLine($"  {nameof(BaudRate)}:   {(int)BaudRate}");
+			sb.AppendLine($"  {nameof(DataBits)}:   {DataBits}");
+			sb.AppendLine($"  {nameof(StopBits)}:   {StopBits}");
+			sb.AppendLine($"  {nameof(Parity)}:     {Parity}");
+			sb.AppendLine($"  {nameof(Client)}:     {Client.GetType().Name}");
+
+			return sb.ToString();
+		}
 	}
 }

AMWD.Protocols.Modbus.Serial/ModbusSerialConnection.cs

@@ -31,8 +31,7 @@ namespace AMWD.Protocols.Modbus.Serial
 		private readonly Task _processingTask;
 		private readonly AsyncQueue<RequestQueueItem> _requestQueue = new();
 
-		// Only required to cover all logic branches on unit tests.
+		private readonly bool _isLinux;
-		private bool _isUnitTest = false;
 
 		#endregion Fields
 
@@ -41,6 +40,8 @@ namespace AMWD.Protocols.Modbus.Serial
 		/// </summary>
 		public ModbusSerialConnection(string portName)
 		{
+			_isLinux = RuntimeInformation.IsOSPlatform(OSPlatform.Linux);
+
 			if (string.IsNullOrWhiteSpace(portName))
 				throw new ArgumentNullException(nameof(portName));
 
@@ -268,7 +269,7 @@ namespace AMWD.Protocols.Modbus.Serial
 				try
 				{
 					// Get next request to process
-					var item = await _requestQueue.DequeueAsync(cancellationToken);
+					var item = await _requestQueue.DequeueAsync(cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 					// Remove registration => already removed from queue
 					item.CancellationTokenRegistration.Dispose();
@@ -276,13 +277,13 @@ namespace AMWD.Protocols.Modbus.Serial
 					// Build combined cancellation token
 					using var linkedCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, item.CancellationTokenSource.Token);
 					// Wait for exclusive access
-					await _portLock.WaitAsync(linkedCts.Token);
+					await _portLock.WaitAsync(linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 					try
 					{
 						// Ensure connection is up
 						await AssertConnection(linkedCts.Token);
 
-						await _serialPort.WriteAsync(item.Request, linkedCts.Token);
+						await _serialPort.WriteAsync(item.Request, linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 
 						linkedCts.Token.ThrowIfCancellationRequested();
 
@@ -291,7 +292,7 @@ namespace AMWD.Protocols.Modbus.Serial
 
 						do
 						{
-							int readCount = await _serialPort.ReadAsync(buffer, 0, buffer.Length, linkedCts.Token);
+							int readCount = await _serialPort.ReadAsync(buffer, 0, buffer.Length, linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 							if (readCount < 1)
 								throw new EndOfStreamException();
 
@@ -322,7 +323,7 @@ namespace AMWD.Protocols.Modbus.Serial
 						_portLock.Release();
 						_idleTimer.Change(IdleTimeout, Timeout.InfiniteTimeSpan);
 
-						await Task.Delay(InterRequestDelay, cancellationToken);
+						await Task.Delay(InterRequestDelay, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 					}
 				}
 				catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
@@ -353,7 +354,7 @@ namespace AMWD.Protocols.Modbus.Serial
 					_serialPort.Close();
 					_serialPort.ResetRS485DriverStateFlags();
 
-					if (DriverEnabledRS485 && (RuntimeInformation.IsOSPlatform(OSPlatform.Linux) || _isUnitTest))
+					if (DriverEnabledRS485 && _isLinux)
 					{
 						var flags = _serialPort.GetRS485DriverStateFlags();
 						flags |= RS485Flags.Enabled;
@@ -361,7 +362,7 @@ namespace AMWD.Protocols.Modbus.Serial
 						_serialPort.ChangeRS485DriverStateFlags(flags);
 					}
 
-					using var connectTask = Task.Run(_serialPort.Open);
+					using var connectTask = Task.Run(_serialPort.Open, cancellationToken);
 					if (await Task.WhenAny(connectTask, Task.Delay(ReadTimeout, cancellationToken)) == connectTask)
 					{
 						await connectTask;
@@ -379,7 +380,7 @@ namespace AMWD.Protocols.Modbus.Serial
 
 					try
 					{
-						await Task.Delay(TimeSpan.FromSeconds(delay), cancellationToken);
+						await Task.Delay(TimeSpan.FromSeconds(delay), cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 					}
 					catch
 					{ /* keep it quiet */ }

AMWD.Protocols.Modbus.Tcp/Extensions/StreamExtensions.cs

@@ -12,7 +12,7 @@ namespace System.IO
 			int offset = 0;
 			do
 			{
-				int count = await stream.ReadAsync(buffer, offset, expectedBytes - offset, cancellationToken);
+				int count = await stream.ReadAsync(buffer, offset, expectedBytes - offset, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (count < 1)
 					throw new EndOfStreamException();
 
@@ -30,7 +30,7 @@ namespace System.IO
 			int offset = 0;
 			do
 			{
-				int count = await stream.ReadAsync(buffer, offset, expectedBytes - offset, cancellationToken);
+				int count = await stream.ReadAsync(buffer, offset, expectedBytes - offset, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (count < 1)
 					throw new EndOfStreamException();
 

AMWD.Protocols.Modbus.Tcp/Extensions/TaskExtensions.cs

@@ -0,0 +1,17 @@
+using System.Threading.Tasks;
+
+namespace AMWD.Protocols.Modbus.Tcp.Extensions
+{
+	internal static class TaskExtensions
+	{
+		public static async void Forget(this Task task)
+		{
+			try
+			{
+				await task;
+			}
+			catch
+			{ /* keep it quiet */ }
+		}
+	}
+}

AMWD.Protocols.Modbus.Tcp/ModbusTcpConnection.cs

@@ -208,7 +208,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 				try
 				{
 					// Get next request to process
-					var item = await _requestQueue.DequeueAsync(cancellationToken);
+					var item = await _requestQueue.DequeueAsync(cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 					// Remove registration => already removed from queue
 					item.CancellationTokenRegistration.Dispose();
@@ -216,19 +216,19 @@ namespace AMWD.Protocols.Modbus.Tcp
 					// Build combined cancellation token
 					using var linkedCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, item.CancellationTokenSource.Token);
 					// Wait for exclusive access
-					await _clientLock.WaitAsync(linkedCts.Token);
+					await _clientLock.WaitAsync(linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 					try
 					{
 						// Ensure connection is up
-						await AssertConnection(linkedCts.Token);
+						await AssertConnection(linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 
 						var stream = _tcpClient.GetStream();
 						await stream.FlushAsync(linkedCts.Token);
 
 #if NET6_0_OR_GREATER
-						await stream.WriteAsync(item.Request, linkedCts.Token);
+						await stream.WriteAsync(item.Request, linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 #else
-						await stream.WriteAsync(item.Request, 0, item.Request.Length, linkedCts.Token);
+						await stream.WriteAsync(item.Request, 0, item.Request.Length, linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 #endif
 
 						linkedCts.Token.ThrowIfCancellationRequested();
@@ -239,9 +239,9 @@ namespace AMWD.Protocols.Modbus.Tcp
 						do
 						{
 #if NET6_0_OR_GREATER
-							int readCount = await stream.ReadAsync(buffer, linkedCts.Token);
+							int readCount = await stream.ReadAsync(buffer, linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 #else
-							int readCount = await stream.ReadAsync(buffer, 0, buffer.Length, linkedCts.Token);
+							int readCount = await stream.ReadAsync(buffer, 0, buffer.Length, linkedCts.Token).ConfigureAwait(continueOnCapturedContext: false);
 #endif
 							if (readCount < 1)
 								throw new EndOfStreamException();
@@ -332,7 +332,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 
 					try
 					{
-						await Task.Delay(TimeSpan.FromSeconds(delay), cancellationToken);
+						await Task.Delay(TimeSpan.FromSeconds(delay), cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 					}
 					catch
 					{ /* keep it quiet */ }

AMWD.Protocols.Modbus.Tcp/ModbusTcpProxy.cs

@@ -10,6 +10,7 @@ using System.Threading.Tasks;
 using AMWD.Protocols.Modbus.Common;
 using AMWD.Protocols.Modbus.Common.Contracts;
 using AMWD.Protocols.Modbus.Common.Protocols;
+using AMWD.Protocols.Modbus.Tcp.Extensions;
 using AMWD.Protocols.Modbus.Tcp.Utils;
 
 namespace AMWD.Protocols.Modbus.Tcp
@@ -17,7 +18,12 @@ namespace AMWD.Protocols.Modbus.Tcp
 	/// <summary>
 	/// Implements a Modbus TCP server proxying all requests to a Modbus client of choice.
 	/// </summary>
-	public class ModbusTcpProxy : IModbusProxy
+	/// <remarks>
+	/// Initializes a new instance of the <see cref="ModbusTcpProxy"/> class.
+	/// </remarks>
+	/// <param name="client">The <see cref="ModbusClientBase"/> used to request the remote device, that should be proxied.</param>
+	/// <param name="listenAddress">An <see cref="IPAddress"/> to listen on.</param>
+	public class ModbusTcpProxy(ModbusClientBase client, IPAddress listenAddress) : IModbusProxy
 	{
 		#region Fields
 
@@ -25,30 +31,17 @@ namespace AMWD.Protocols.Modbus.Tcp
 
 		private TimeSpan _readWriteTimeout = TimeSpan.FromSeconds(100);
 
-		private TcpListenerWrapper _tcpListener;
+		private readonly TcpListenerWrapper _tcpListener = new(listenAddress, 502);
 		private CancellationTokenSource _stopCts;
 		private Task _clientConnectTask = Task.CompletedTask;
 
 		private readonly SemaphoreSlim _clientListLock = new(1, 1);
 		private readonly List<TcpClientWrapper> _clients = [];
-		private readonly List<Task> _clientTasks = [];
 
 		#endregion Fields
 
 		#region Constructors
 
-		/// <summary>
-		/// Initializes a new instance of the <see cref="ModbusTcpProxy"/> class.
-		/// </summary>
-		/// <param name="client">The <see cref="ModbusClientBase"/> used to request the remote device, that should be proxied.</param>
-		/// <param name="listenAddress">An <see cref="IPAddress"/> to listen on.</param>
-		public ModbusTcpProxy(ModbusClientBase client, IPAddress listenAddress)
-		{
-			Client = client ?? throw new ArgumentNullException(nameof(client));
-
-			_tcpListener = new TcpListenerWrapper(listenAddress, 502);
-		}
-
 		#endregion Constructors
 
 		#region Properties
@@ -56,7 +49,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 		/// <summary>
 		/// Gets the Modbus client used to request the remote device, that should be proxied.
 		/// </summary>
-		public ModbusClientBase Client { get; }
+		public ModbusClientBase Client { get; } = client ?? throw new ArgumentNullException(nameof(client));
 
 		/// <summary>
 		/// Gets the <see cref="IPAddress"/> to listen on.
@@ -140,16 +133,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 
 			try
 			{
-				await Task.WhenAny(_clientConnectTask, Task.Delay(Timeout.Infinite, cancellationToken));
+				await Task.WhenAny(_clientConnectTask, Task.Delay(Timeout.Infinite, cancellationToken)).ConfigureAwait(continueOnCapturedContext: false);
-			}
-			catch (OperationCanceledException)
-			{
-				// Terminated
-			}
-
-			try
-			{
-				await Task.WhenAny(Task.WhenAll(_clientTasks), Task.Delay(Timeout.Infinite, cancellationToken));
 			}
 			catch (OperationCanceledException)
 			{
@@ -174,6 +158,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 			_tcpListener.Dispose();
 
 			_stopCts?.Dispose();
+			GC.SuppressFinalize(this);
 		}
 
 		private void Assertions()
@@ -196,12 +181,13 @@ namespace AMWD.Protocols.Modbus.Tcp
 			{
 				try
 				{
-					var client = await _tcpListener.AcceptTcpClientAsync(cancellationToken);
+					var client = await _tcpListener.AcceptTcpClientAsync(cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
-					await _clientListLock.WaitAsync(cancellationToken);
+					await _clientListLock.WaitAsync(cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 					try
 					{
 						_clients.Add(client);
-						_clientTasks.Add(HandleClientAsync(client, cancellationToken));
+						// Can be ignored as it will terminate by itself on cancellation
+						HandleClientAsync(client, cancellationToken).Forget();
 					}
 					finally
 					{
@@ -227,20 +213,20 @@ namespace AMWD.Protocols.Modbus.Tcp
 					using (var cts = new CancellationTokenSource(ReadWriteTimeout))
 					using (cancellationToken.Register(cts.Cancel))
 					{
-						byte[] headerBytes = await stream.ReadExpectedBytesAsync(6, cts.Token);
+						byte[] headerBytes = await stream.ReadExpectedBytesAsync(6, cts.Token).ConfigureAwait(continueOnCapturedContext: false);
 						requestBytes.AddRange(headerBytes);
 
 						ushort length = headerBytes
 							.Skip(4).Take(2).ToArray()
 							.GetBigEndianUInt16();
 
-						byte[] bodyBytes = await stream.ReadExpectedBytesAsync(length, cts.Token);
+						byte[] bodyBytes = await stream.ReadExpectedBytesAsync(length, cts.Token).ConfigureAwait(continueOnCapturedContext: false);
 						requestBytes.AddRange(bodyBytes);
 					}
 
-					byte[] responseBytes = await HandleRequestAsync([.. requestBytes], cancellationToken);
+					byte[] responseBytes = await HandleRequestAsync([.. requestBytes], cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 					if (responseBytes != null)
-						await stream.WriteAsync(responseBytes, 0, responseBytes.Length, cancellationToken);
+						await stream.WriteAsync(responseBytes, 0, responseBytes.Length, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				}
 			}
 			catch
@@ -249,7 +235,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 			}
 			finally
 			{
-				await _clientListLock.WaitAsync(cancellationToken);
+				await _clientListLock.WaitAsync(cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				try
 				{
 					_clients.Remove(client);
@@ -324,7 +310,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 			responseBytes.AddRange(requestBytes.Take(8));
 			try
 			{
-				var coils = await Client.ReadCoilsAsync(unitId, firstAddress, count, cancellationToken);
+				var coils = await Client.ReadCoilsAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[(int)Math.Ceiling(coils.Count / 8.0)];
 				for (int i = 0; i < coils.Count; i++)
@@ -363,7 +349,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 			responseBytes.AddRange(requestBytes.Take(8));
 			try
 			{
-				var discreteInputs = await Client.ReadDiscreteInputsAsync(unitId, firstAddress, count, cancellationToken);
+				var discreteInputs = await Client.ReadDiscreteInputsAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[(int)Math.Ceiling(discreteInputs.Count / 8.0)];
 				for (int i = 0; i < discreteInputs.Count; i++)
@@ -402,7 +388,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 			responseBytes.AddRange(requestBytes.Take(8));
 			try
 			{
-				var holdingRegisters = await Client.ReadHoldingRegistersAsync(unitId, firstAddress, count, cancellationToken);
+				var holdingRegisters = await Client.ReadHoldingRegistersAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[holdingRegisters.Count * 2];
 				for (int i = 0; i < holdingRegisters.Count; i++)
@@ -436,7 +422,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 			responseBytes.AddRange(requestBytes.Take(8));
 			try
 			{
-				var inputRegisters = await Client.ReadInputRegistersAsync(unitId, firstAddress, count, cancellationToken);
+				var inputRegisters = await Client.ReadInputRegistersAsync(unitId, firstAddress, count, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				byte[] values = new byte[count * 2];
 				for (int i = 0; i < count; i++)
@@ -484,7 +470,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 					LowByte = requestBytes[11],
 				};
 
-				bool isSuccess = await Client.WriteSingleCoilAsync(requestBytes[6], coil, cancellationToken);
+				bool isSuccess = await Client.WriteSingleCoilAsync(requestBytes[6], coil, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -524,7 +510,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 					LowByte = requestBytes[11]
 				};
 
-				bool isSuccess = await Client.WriteSingleHoldingRegisterAsync(requestBytes[6], register, cancellationToken);
+				bool isSuccess = await Client.WriteSingleHoldingRegisterAsync(requestBytes[6], register, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -584,7 +570,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 					});
 				}
 
-				bool isSuccess = await Client.WriteMultipleCoilsAsync(requestBytes[6], coils, cancellationToken);
+				bool isSuccess = await Client.WriteMultipleCoilsAsync(requestBytes[6], coils, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -641,7 +627,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 					});
 				}
 
-				bool isSuccess = await Client.WriteMultipleHoldingRegistersAsync(requestBytes[6], list, cancellationToken);
+				bool isSuccess = await Client.WriteMultipleHoldingRegistersAsync(requestBytes[6], list, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 				if (isSuccess)
 				{
 					// Response is an echo of the request
@@ -698,7 +684,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 
 			try
 			{
-				var deviceInfo = await Client.ReadDeviceIdentificationAsync(requestBytes[6], category, firstObject, cancellationToken);
+				var deviceInfo = await Client.ReadDeviceIdentificationAsync(requestBytes[6], category, firstObject, cancellationToken).ConfigureAwait(continueOnCapturedContext: false);
 
 				var bodyBytes = new List<byte>();
 
@@ -761,7 +747,7 @@ namespace AMWD.Protocols.Modbus.Tcp
 			}
 		}
 
-		private byte[] GetDeviceObject(byte objectId, DeviceIdentification deviceIdentification)
+		private static byte[] GetDeviceObject(byte objectId, DeviceIdentification deviceIdentification)
 		{
 			var result = new List<byte> { objectId };
 			switch ((ModbusDeviceIdentificationObject)objectId)
@@ -851,5 +837,18 @@ namespace AMWD.Protocols.Modbus.Tcp
 		}
 
 		#endregion Request Handling
+
+		/// <inheritdoc/>
+		public override string ToString()
+		{
+			var sb = new StringBuilder();
+
+			sb.AppendLine($"TCP Proxy");
+			sb.AppendLine($"  {nameof(ListenAddress)}:   {ListenAddress}");
+			sb.AppendLine($"  {nameof(ListenPort)}:      {ListenPort}");
+			sb.AppendLine($"  {nameof(Client)}:          {Client.GetType().Name}");
+
+			return sb.ToString();
+		}
 	}
 }

AMWD.Protocols.Modbus.Tcp/Utils/TcpClientWrapperFactory.cs

@@ -3,6 +3,9 @@ using System.Net.Sockets;
 
 namespace AMWD.Protocols.Modbus.Tcp.Utils
 {
+	/// <summary>
+	/// Factory for creating <see cref="TcpClientWrapper"/> instances.
+	/// </summary>
 	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
 	internal class TcpClientWrapperFactory
 	{