@Override
    public void hello(HelloRequest request, StreamObserver<HelloReply> responseObserver) {
        if (request.getName().isEmpty()) {
            responseObserver.onError(
                    Status.FAILED_PRECONDITION.withDescription("Name cannot be empty").asRuntimeException());
        } else {
            responseObserver.onNext(buildReply(toMessage(request.getName())));
            responseObserver.onCompleted();
        }
    }
Sends a {@link HelloReply} immediately when receiving a request.
examples/grpc/src/main/java/example/armeria/grpc/HelloServiceImpl.java