Added modbus-proxy CLI tool

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

@@ -0,0 +1,24 @@
+using System;
+using System.Threading.Tasks;
+using System.Threading;
+
+namespace AMWD.Protocols.Modbus.Common.Contracts
+{
+	/// <summary>
+	/// Represents a Modbus proxy.
+	/// </summary>
+	public interface IModbusProxy : IDisposable
+	{
+		/// <summary>
+		/// Starts the proxy.
+		/// </summary>
+		/// <param name="cancellationToken">A cancellation token used to propagate notification that this operation should be canceled.</param>
+		Task StartAsync(CancellationToken cancellationToken = default);
+
+		/// <summary>
+		/// Stops the proxy.
+		/// </summary>
+		/// <param name="cancellationToken">A cancellation token used to propagate notification that this operation should be canceled.</param>
+		Task StopAsync(CancellationToken cancellationToken = default);
+	}
+}