WebClient is a reactive client that provides an alternative to RestTemplate.
It is said that it's asynchronous.

But I doubt it with below code:

```
 WebClient.create()
            .method(HttpMethod.GET)
            .uri("http://localhost:8080/testApi")
            .retrieve()
            .bodyToMono(String.class)

```

It does nothing. Not any http request is sent. It seems it isn't triggerd. Unless I trigger it by add `.block()`. But it make things not 'Async'.

Also,What I know is using `.subscribe()` that make things looks async. 

But is the WebClient designed for this? What's the best pratices to use WebClient.