class JsonRpc

Rack middleware implementing the A2A JSON-RPC 2.0 protocol binding.

Strips the JSON-RPC envelope from the inbound request, setting env keys for the method name, request id, and parsed params. Calls downstream. On return, wraps env["a2a.result"] back into a JSON-RPC response envelope.

Streaming operations (SendStreamingMessage, SubscribeToTask): When the handler sets env["a2a.stream"] to an SSE::Stream (which is a Protocol::HTTP::Body::Writable, which is a Readable), Falcon's protocol-rack passes it through untouched. True async streaming with backpressure — no Thread::Queue, no #each polling.