Protocol Buffer example of importing and using empty

empty-example.md

How to import and indicate empty request or reply messages:

import "google/protobuf/empty.proto";

service SomeService {
    rpc SomeOperation (google.protobuf.Empty) returns (google.protobuf.Empty) {}
}

Assuming we're talking about gRPC, there's still data sent over the wire.

The response body has a five-byte prefix, which should be all zeros: the first byte indicates whether the message is compressed, and the next four bytes are a 32-bit unsigned integer. Empty protobuf messages serialize to zero bytes, and google.protobuf.Empty is always empty, so there's no data following the initial 5 bytes.

You'll also end up sending at least one trailer with the status code (grpc-status: 0). Depending on your implementation, you may also send the grpc-message and grpc-status-details-bin trailers.