Add WebSocketStream

[stephentoub]

Fixes #111217

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[Copilot]

Pull Request Overview

This PR adds a new WebSocketStream abstraction to forward Stream operations over a WebSocket and includes accompanying tests, resource updates, and API surface adjustments.

• Introduces WebSocketStream and related specialized stream types (ReadWriteStream, WriteMessageStream, ReadMessageStream)
• Adds comprehensive tests in WebSocketStreamTests.cs and integrates them into the test project
• Extends ManagedWebSocket to centralize message-type validation and updates resources and reference assemblies

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/libraries/System.Net.WebSockets/src/System/Net/WebSockets/WebSocketStream.cs	Added WebSocketStream implementation
src/libraries/System.Net.WebSockets/src/System/Net/WebSockets/ManagedWebSocket.cs	Extracted ThrowIfInvalidMessageType helper
src/libraries/System.Net.WebSockets/src/Resources/Strings.resx	Added net_WebSockets_TimeoutOutOfRange string
src/libraries/System.Net.WebSockets/ref/System.Net.WebSockets.cs	Updated reference assembly for WebSocketStream
src/libraries/System.Net.WebSockets/tests/System.Net.WebSockets.Tests.csproj	Updated test project to include new tests
src/libraries/System.Net.WebSockets/tests/WebSocketStreamTests.cs	Added tests for new WebSocketStream behavior
src/libraries/Common/tests/StreamConformanceTests/System/IO/StreamConformanceTests.cs	Updated conformance tests to async patterns

Comments suppressed due to low confidence (4)

src/libraries/System.Net.WebSockets/src/Resources/Strings.resx:142

• [nitpick] The error message is unclear; consider rephrasing to "The timeout must be non-negative or Timeout.InfiniteTimeSpan." for better readability.

    <value>The timeout must be a value between non-negative or Timeout.InfiniteTimeSpan.</value>

src/libraries/System.Net.WebSockets/tests/System.Net.WebSockets.Tests.csproj:11

• The project references WebSocketCreateTest.cs which does not exist; it should reference the actual test file (WebSocketStreamCreateTests.cs) to include the new tests and avoid compilation failures.

    <Compile Include="WebSocketCreateTest.cs" />

src/libraries/System.Net.WebSockets/ref/System.Net.WebSockets.cs:51

• The reference assembly declares a parameterless WebSocketStream constructor, but the implementation only defines a constructor taking a WebSocket parameter. This mismatch will cause API and compilation inconsistencies.

        private protected WebSocketStream() { }

src/libraries/System.Net.WebSockets/src/System/Net/WebSockets/WebSocketStream.cs:273

• The call to ConfigureAwait uses ConfigureAwaitOptions.SuppressThrowing, but ConfigureAwait expects a bool. Replace with ConfigureAwait(false) (or true if appropriate) to match the API.

                                await WebSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, null, ct).ConfigureAwait(ConfigureAwaitOptions.SuppressThrowing);

[stephentoub]

@CarnaViire, any feedback? Thoughts on @MihaZupan's question?

[CarnaViire]

@CarnaViire, any feedback? Thoughts on @MihaZupan's question?

Sorry for the delay. I will bulk post the review today.

[CarnaViire]

LGTM in general with couple of nits
Thanks!!

[CarnaViire]

should this also have .ConfigureAwait(ConfigureAwaitOptions.SuppressThrowing); to ensure it won't throw?

[CarnaViire]

@stephentoub I'm going to apply the suggestion from #116729 (comment) to move forward with this.

If there are any concerns, we can address them in a follow-up.