Major performance improvements for SignalR message transport:
- BrotliHelper now uses ArrayPool and stackalloc for zero-allocation compression/decompression; added span/IBufferWriter overloads and pooled buffer support.
- AcJsonDeserializer supports direct deserialization from UTF-8 spans, with fast path for no reference handling.
- SignalResponseDataMessage uses pooled buffers for Brotli decompression and zero-copy deserialization; implements IDisposable for buffer return.
- IdMessage serialization optimized for primitives and Guids to avoid unnecessary allocations.
- Added JsonTo<T> span/byte[] extension methods for zero-allocation deserialization.
- All changes are backward compatible and reduce GC pressure for high-throughput scenarios.
Major refactor: all SignalR responses now use a single unified `SignalResponseDataMessage` type with binary payloads. JSON responses are Brotli-compressed for efficiency. Removed legacy JSON/Binary response types and MessagePack server-to-client serialization. Updated all serialization extensions for zero-allocation binary ops. Refactored client/server/data source/test code to use new message and serialization model. Improved deserialization robustness for primitives. Modernized and streamlined test suite.
Loretta