Improve javadoc for HttpAsyncResponse

Author: rbygrave

client/src/main/java/io/avaje/http/client/HttpAsyncResponse.java

@@ -10,16 +10,53 @@ public interface HttpAsyncResponse {
 
   /**
    * Process discarding response body as {@literal HttpResponse<Void>}.
+   *
+   * <pre>{@code
+   *
+   *   clientContext.request()
+   *       .path("hello/world")
+   *       .GET()
+   *       .async().asDiscarding()
+   *       .whenComplete((hres, throwable) -> {
+   *
+   *         if (throwable != null) {
+   *           ...
+   *         } else {
+   *           int statusCode = hres.statusCode();
+   *           ...
+   *         }
+   *       });
+   *
+   * }</pre>
    */
   CompletableFuture<HttpResponse<Void>> asDiscarding();
 
   /**
    * Process as String response body {@literal HttpResponse<String>}.
+   *
+   * <pre>{@code
+   *
+   *   clientContext.request()
+   *       .path("hello/world")
+   *       .GET()
+   *       .async().asString()
+   *       .whenComplete((hres, throwable) -> {
+   *
+   *         if (throwable != null) {
+   *           ...
+   *         } else {
+   *           int statusCode = hres.statusCode();
+   *           String body = hres.body();
+   *           ...
+   *         }
+   *       });
+   *
+   * }</pre>
    */
   CompletableFuture<HttpResponse<String>> asString();
 
   /**
-   * Process expecting a (json) bean response body.
+   * Process expecting a bean response body (typically from json content).
    * <p>
    * If the HTTP statusCode is 300 or above a HttpException is throw which
    * contains the HttpResponse.

client/src/test/java/io/avaje/http/client/HelloControllerTest.java

@@ -52,12 +52,20 @@ void get_helloMessage() {
   @Test
   void async_get_asString() throws ExecutionException, InterruptedException {
 
+    AtomicReference<HttpResponse<String>> ref = new AtomicReference<>();
+
     final CompletableFuture<HttpResponse<String>> future = clientContext.request()
       .path("hello").path("message")
       .GET()
-      .async().asString();
+      .async().asString()
+      .whenComplete((hres, throwable) -> {
+        ref.set(hres);
+        assertThat(hres.statusCode()).isEqualTo(200);
+        assertThat(hres.body()).contains("hello world");
+      });
 
     final HttpResponse<String> hres = future.get();
+    assertThat(hres).isSameAs(ref.get());
     assertThat(hres.body()).contains("hello world");
     assertThat(hres.statusCode()).isEqualTo(200);
   }