Major protocol update: OnReceiveMessage now takes metadata (SignalReceiveParams) and payload (byte[]) as separate hub arguments, not a single envelope. Metadata is AcBinary-serialized; payload uses protocol fast-path. Updated all client/server code, interfaces, and docs. Added ISignalParams and SignalReceiveParams types. Improved AcBinaryHubProtocol diagnostics and made byte[] fast-path more robust. This enables clearer, more debuggable, and future-proof SignalR binary messaging.
