gRPC design

Design decision: gRPC rides the ASGI bridge, not a new Actor

gRPC uses HTTP/2 stream lifetime, flow control and trailers. Do not add a connection dispatcher or duplicate those mechanisms in the gRPC layer. Each call owns isolated stream work, not the connection.

Keep message framing, compression, metadata, status and deadlines in blackbull.grpc. Handlers exchange bytes; protobuf adapters stay optional.

Streaming and cancellation

Unary, server-streaming, client-streaming and bidirectional calls share the same transport. Await its send path for backpressure; diagnostic window snapshots are not an admission mechanism.

Cancellation must finalize response generators and release per-call work. grpc-timeout bounds the whole call, including streaming. Failures after the first message still need status trailers.

Read blackbull/grpc/asgi.py for call lifetime and registry.py for handler classification. Public contracts are in the gRPC guide; external-client checks live in tests/conformance/grpc/.