Set StreamClientSessionTransport to the connected state before reading messages

- This might fix the WithProgress_ProgressReported failures

  Failed ModelContextProtocol.Tests.Client.McpClientExtensionsTests.WithProgress_ProgressReported [22 ms]
  Error Message:
   System.IO.IOException : Transport is already disconnected and can't be reconnected.
  Stack Trace:
     at ModelContextProtocol.Protocol.TransportBase.SetConnected() in /_/src/ModelContextProtocol/Protocol/TransportBase.cs:line 125
   at ModelContextProtocol.Client.StreamClientSessionTransport..ctor(TextWriter serverInput, TextReader serverOutput, String endpointName, ILoggerFactory loggerFactory) in /_/src/ModelContextProtocol/Client/StreamClientSessionTransport.cs:line 54
   at ModelContextProtocol.Protocol.StreamClientTransport.ConnectAsync(CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/StreamClientTransport.cs:line 49
   at ModelContextProtocol.Client.McpClient.ConnectAsync(CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/McpClient.cs:line 105
   at ModelContextProtocol.Client.McpClient.ConnectAsync(CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/McpClient.cs:line 164
   at ModelContextProtocol.Client.McpClientFactory.CreateAsync(IClientTransport clientTransport, McpClientOptions clientOptions, ILoggerFactory loggerFactory, CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/McpClientFactory.cs:line 37
   at ModelContextProtocol.Client.McpClientFactory.CreateAsync(IClientTransport clientTransport, McpClientOptions clientOptions, ILoggerFactory loggerFactory, CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/McpClientFactory.cs:line 46
   at ModelContextProtocol.Tests.ClientServerTestBase.CreateMcpClientForServer() in /_/tests/ModelContextProtocol.Tests/ClientServerTestBase.cs:line 67
   at ModelContextProtocol.Tests.Client.McpClientExtensionsTests.WithProgress_ProgressReported() in /_/tests/ModelContextProtocol.Tests/Client/McpClientExtensionsTests.cs:line 356
--- End of stack trace from previous location ---
  Standard Output Messages:
 | [2025-05-28T16:24:33] ModelContextProtocol.Client.StreamClientSessionTransport Information: Client (stream) transport reading messages.
 | [2025-05-28T16:24:33] ModelContextProtocol.Client.StreamClientSessionTransport Warning: Client (stream) transport message reading failed.
 System.InvalidOperationException: Transport is not connected.
    at ModelContextProtocol.Protocol.TransportBase.WriteMessageAsync(JsonRpcMessage message, CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Protocol/TransportBase.cs:line 91
    at ModelContextProtocol.Client.StreamClientSessionTransport.ProcessMessageAsync(String line, CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/StreamClientSessionTransport.cs:line 134
    at ModelContextProtocol.Client.StreamClientSessionTransport.ReadMessagesAsync(CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/StreamClientSessionTransport.cs:line 108
 | [2025-05-28T16:24:33] ModelContextProtocol.Client.StreamClientSessionTransport Information: Client (stream) shutting down.
 | [2025-05-28T16:24:33] ModelContextProtocol.Client.StreamClientSessionTransport Information: Client (stream) shut down.
 | [2025-05-28T16:24:33] ModelContextProtocol.Client.McpClient Error: in-memory-stream client initialization error.
 System.IO.IOException: Transport is already disconnected and can't be reconnected.
    at ModelContextProtocol.Protocol.TransportBase.SetConnected() in /_/src/ModelContextProtocol/Protocol/TransportBase.cs:line 125
    at ModelContextProtocol.Client.StreamClientSessionTransport..ctor(TextWriter serverInput, TextReader serverOutput, String endpointName, ILoggerFactory loggerFactory) in /_/src/ModelContextProtocol/Client/StreamClientSessionTransport.cs:line 54
    at ModelContextProtocol.Protocol.StreamClientTransport.ConnectAsync(CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/StreamClientTransport.cs:line 49
    at ModelContextProtocol.Client.McpClient.ConnectAsync(CancellationToken cancellationToken) in /_/src/ModelContextProtocol/Client/McpClient.cs:line 105

- https://github.com/modelcontextprotocol/csharp-sdk/actions/runs/15305366319/job/43056566292?pr=456

Author: halter73

src/ModelContextProtocol/Client/StreamClientSessionTransport.cs

@@ -17,7 +17,7 @@ internal class StreamClientSessionTransport : TransportBase
     /// Initializes a new instance of the <see cref="StreamClientSessionTransport"/> class.
     /// </summary>
     /// <param name="serverInput">
-    /// The text writer connected to the server's input stream. 
+    /// The text writer connected to the server's input stream.
     /// Messages written to this writer will be sent to the server.
     /// </param>
     /// <param name="serverOutput">
@@ -41,17 +41,17 @@ public StreamClientSessionTransport(
         _serverOutput = serverOutput;
         _serverInput = serverInput;
 
+        SetConnected();
+
         // Start reading messages in the background. We use the rarer pattern of new Task + Start
         // in order to ensure that the body of the task will always see _readTask initialized.
         // It is then able to reliably null it out on completion.
         var readTask = new Task<Task>(
-            thisRef => ((StreamClientSessionTransport)thisRef!).ReadMessagesAsync(_shutdownCts.Token), 
+            thisRef => ((StreamClientSessionTransport)thisRef!).ReadMessagesAsync(_shutdownCts.Token),
             this,
             TaskCreationOptions.DenyChildAttach);
         _readTask = readTask.Unwrap();
         readTask.Start();
-
-        SetConnected();
     }
 
     /// <inheritdoc/>
@@ -80,7 +80,7 @@ public override async Task SendMessageAsync(JsonRpcMessage message, Cancellation
     }
 
     /// <inheritdoc/>
-    public override ValueTask DisposeAsync() => 
+    public override ValueTask DisposeAsync() =>
         CleanupAsync(cancellationToken: CancellationToken.None);
 
     private async Task ReadMessagesAsync(CancellationToken cancellationToken)