@Override
    public Mono<HelloReply> lotsOfGreetings(Flux<HelloRequest> request) {
        return request
                .map(HelloRequest::getName)
                .collect(Collectors.joining(", "))
                .map(it -> buildReply(toMessage(it)));
    }
Sends a {@link HelloReply} when a request has been completed with multiple {@link HelloRequest}s.
examples/grpc-reactor/src/main/java/example/armeria/grpc/reactor/HelloServiceImpl.java