Use Vertx Grpc Server But do not use Vertx Grpc Client,Loop 10 call ,but blocked at first

### Questions

I am Grpc Server Use Vertx Grpc Serve build.Grpc Client do not use Vertx Grpc Client.Then I Loop 10 call ,but blocked at first。

### Version

4.3.7

### Context

- Server
```
public class VertxStart extends AbstractVerticle {
@Override
public void start() {
final var server = GrpcServer.server(vertx);
final var greeter = new GreeterGrpc.GreeterImplBase() {
@Override
public void sayHello(final HelloRequest request, final StreamObserver responseObserver) {
System.out.println("Hello " + request.getName());
final var reply = HelloReply.newBuilder().setMessage(request.getName()).build();
responseObserver.onNext(reply);
responseObserver.onCompleted();
}

};
GrpcServiceBridge
.bridge(greeter)
.bind(server);
vertx.createHttpServer().requestHandler(server).listen(4240);
}
}
```
- Client
```public class GreeterClient {
public static void main(String[] args) {

new GreeterClient().start();
}

public void start() {
final var channel = NettyChannelBuilder.forAddress("127.0.0.1", 4240).usePlaintext()
.build();
final var sub = GreeterGrpc.newBlockingStub(channel);
for (int i = 0; i < 10; i++) {
System.out.println("开始idx\t" + i);
final var data = HelloRequest.newBuilder().setName("qwx" + i).build();
final var resp = sub.sayHello(data);
System.out.println("resp\t" + resp.getMessage());
System.out.println("结束idx\t" + i);
}
channel.shutdown() ;
}
}
```

### Extra

* JDK 11