@Override
    public StreamObserver<HelloRequest> lotsOfGreetings(StreamObserver<HelloReply> responseObserver) {
        return new StreamObserver<HelloRequest>() {
            final ArrayList<String> names = new ArrayList<>();

            @Override
            public void onNext(HelloRequest value) {
                names.add(value.getName());
            }

            @Override
            public void onError(Throwable t) {
                responseObserver.onError(t);
            }

            @Override
            public void onCompleted() {
                responseObserver.onNext(buildReply(toMessage(String.join(", ", names))));
                responseObserver.onCompleted();
            }
        };
    }
Sends a {@link HelloReply} when a request has been completed with multiple {@link HelloRequest}s.
armeria-example/armeria-grpc-server/src/main/java/com/example/grpc/armeria/HelloServiceImpl.java