websocket-sharp v1.3.1

This patch release fixes ordering and lifecycle behavior for asynchronous sends
while preserving the existing public API and Unity assembly identity.

Highlights

Sequential SendAsync calls accepted by one physical connection are written
in FIFO order by a single bounded dispatcher.
Completion callbacks run independently from the network writer, so a slow or
throwing callback does not block later physical sends.
MaxAsyncSendQueueLength continues to bound queued, active, and
callback-pending operations.
Closing a connection rejects new sends and completes waiting operations with
false while disposing their payload streams.
Reconnect creates a fresh dispatcher. Data queued for an old connection
cannot be compressed or written through the new connection.
Regression coverage includes immediate binary sends from server OnOpen,
FIFO ordering, queue overflow, blocked and throwing callbacks, close/reconnect
cancellation, stale compressed payloads, and ordered concurrent-client stress.

135/135 net472 unit tests passed.
10/10 net472 stress tests passed.
Immediate server OnOpen probe: 1000/1000 first messages received.
FIFO probe: 20000/20000 sequential async-send pairs arrived in call order.
Sustained ordering stress: 100 CCU completed 100000 ordered messages
without loss, duplication, ordering errors, or stranded sessions.
Public API snapshot and Unity/IL2CPP compatibility gates passed.

Target framework: net472.
Unity: managed plugin for .NET 4.x-compatible Editor, Standalone, and tested
mobile/IL2CPP targets.
WebGL: not supported by this managed TCP socket implementation.
Assembly name and strong name remain unchanged.
AssemblyVersion remains 1.0.2.32832 for existing Unity binary references.
File and product version: 1.3.1.0.

websocket-sharp.dll: the signed net472 library.
websocket-sharp-v1.3.1-unity-net472.zip: DLL, license, README, and these
release notes.
SHA256SUMS.txt: SHA-256 checksums for the DLL and ZIP.