Description

ClientWebSocket hangs when attempting to connect to HTTP/1.1 WebSocket server using RequestVersionOrHigher policy. If this is expected behavior, it should probably be documented.

Reproduction Steps

This will hang unless HttpVersionPolicy setting is commented out:

using System.Net.WebSockets;

using var ws = new ClientWebSocket();
ws.Options.HttpVersion       = new(1, 1);
ws.Options.HttpVersionPolicy = HttpVersionPolicy.RequestVersionOrHigher; // <--- causes problem

using var handler = new SocketsHttpHandler();
handler.ConnectTimeout = TimeSpan.FromSeconds(10);

using var invoker = new HttpMessageInvoker(handler);
await ws.ConnectAsync(new("wss://echo.websocket.org"), invoker, CancellationToken.None); // <-- hangs
Console.WriteLine(ws.State);

Expected behavior

Correctly determining that server doesn't support HTTP/2 and falling back to HTTP/1.1.

Actual behavior

Hangs indefinitely.

Regression?

Didn't test on .NET 7 yet, but seems to behave similarly on .NET 8 and .NET 9.

Known Workarounds

Using inverse options seems to work:

ws.Options.HttpVersion       = new(2, 0);
ws.Options.HttpVersionPolicy = HttpVersionPolicy.RequestVersionOrLower;

Configuration

Tested on .NET 8, 9: win-x64, linux-x64, linux-arm64.

Other information

No response