Disposing transports can hang when running in .NET framework

[eiriktsarpalis]

This is because the read loop in the core transport abstraction uses TextWriter:

csharp-sdk/src/ModelContextProtocol/Protocol/Transport/StreamClientSessionTransport.cs

Line 99 in 08f9cdb

if (await _serverOutput.ReadLineAsync(cancellationToken).ConfigureAwait(false) is not string line)

csharp-sdk/src/ModelContextProtocol/Protocol/Transport/StreamServerTransport.cs

Line 103 in 08f9cdb

var line = await _inputReader.ReadLineAsync(shutdownToken).ConfigureAwait(false);

Which in netstandard2.0 is not cancellable and requires a polyfill that does not properly honor the cancellation token:

csharp-sdk/src/Common/Polyfills/System/IO/TextReaderExtensions.cs

Lines 5 to 13 in 08f9cdb

	public static Task<string> ReadLineAsync(this TextReader reader, CancellationToken cancellationToken)
	{
	if (cancellationToken.IsCancellationRequested)
	{
	return Task.FromCanceled<string>(cancellationToken);
	}
	return reader.ReadLineAsync();
	}

[sneh0195]

I am manually calling Dispose on IMcpClient since our project uses ".NET Framework 4.7.2"

await mcpClient.DisposeAsync().ConfigureAwait(false);

I am facing the same issue that service hangs and code after this await is not executed all. No exception in thrown.

Is there any workaround for this issue?

[eiriktsarpalis]

This has been fixed by #588.

[sneh0195]

Still facing this issue with SSE transport in .net framework 4.7.2. Works well with streamble http