Major serialization pipeline refactor: all hot-path buffer and position management is now owned by BinarySerializationContext<TOutput>, with all write methods inlined for zero virtual dispatch. TOutput (now struct, IBinaryOutputBase) handles only cold-path buffer management (Initialize, Grow, GetTotalPosition). ArrayBinaryOutput and BufferWriterBinaryOutput are simplified to buffer managers. IBinaryOutput and BinaryOutputBase are removed. All serialization logic now uses context write methods (~130 call sites updated). This yields significant performance gains by eliminating virtual/interface calls on the serialization hot path.
Major internal refactor: AcBinarySerializer and BinarySerializationContext are now generic on TOutput : BinaryOutputBase, enabling JIT devirtualization and eliminating virtual dispatch in hot serialization loops. All serialization logic (WriteValue, WriteObject, WriteArray, etc.) is now generic on TOutput and delegates buffer operations to the output instance (ArrayBinaryOutput or BufferWriterBinaryOutput). Context pooling is now per output type. All buffer management is moved to output classes. The public API is unchanged, but the internal architecture is now fully generic and ready for further JIT optimizations. Also disables the source generator and sets UseMetadata=false by default.
Introduce ArrayBinaryOutput, BufferWriterBinaryOutput, BinaryOutputBase, and IBinaryOutput for flexible, efficient serialization to pooled arrays and streaming buffers. Refactor AcBinaryHubProtocol to use new output for SignalR. Make UseMetadata runtime-settable in AcBinarySerializerOptions. Update QuickBenchmark for new options. Enables allocation-free, extensible binary serialization infrastructure.