With protocol values and message framing complete, Stage 2 delivered the first end-to-end call: plaintext h2c unary RPC. This is already on main , and Stage 3 and Stage 4 subsequently completed all four RPC cardinalities on the same transport primitive. Previous: Building a Leak-Safe gRPC Frame Decoder on Reactor Netty Method Descriptor Is Where Protocol Meets Types A method requires a precise service name, method name, cardinality, and request/response marshallers: ...