ensure async response is closed

src/main/java/com/auth0/net/client/DefaultHttpClient.java

@@ -100,6 +100,8 @@ public void onResponse(@NotNull Call call, @NotNull Response response) {
                     future.complete(buildResponse(response));
                 } catch (IOException e) {
                     future.completeExceptionally(e);
+                } finally {
+                    response.close();
                 }
             }
         });

src/test/java/com/auth0/net/client/DefaultHttpClientTest.java

@@ -462,6 +462,31 @@ public void alwaysCloseResponseOnSuccessfulRequest() throws IOException {
         verify(response, times(1)).close();
     }
 
+    @Test
+    public void alwaysCloseResponseOnSuccessfulRequestAsync() throws Exception {
+        OkHttpClient okClient = Mockito.mock(OkHttpClient.class);
+        okhttp3.Response response = Mockito.mock(okhttp3.Response.class);
+        Call call = Mockito.mock(Call.class);
+
+        doReturn(call).when(okClient).newCall(any());
+
+        doAnswer(invocation -> {
+            ((Callback) invocation.getArgument(0)).onResponse(call, response);
+            return null;
+        }).when(call).enqueue(any(Callback.class));
+
+        Headers headers = Mockito.mock(Headers.class);
+        when(response.headers()).thenReturn(headers);
+
+        DefaultHttpClient client = new DefaultHttpClient(okClient);
+        Auth0HttpRequest request = Auth0HttpRequest.newBuilder(server.url("/users/").toString(), HttpMethod.POST)
+            .withBody(HttpRequestBody.create("application/json", "{}".getBytes()))
+            .build();
+
+        client.sendRequestAsync(request).get();
+        verify(response, times(1)).close();
+    }
+
     @Test
     public void closesResponseOnAPIError() throws Exception {
         okhttp3.Response response = Mockito.mock(okhttp3.Response.class);
@@ -490,6 +515,36 @@ public void closesResponseOnAPIError() throws Exception {
         verify(response, times(1)).close();
     }
 
+    @Test
+    public void closesResponseOnAPIErrorAsync() throws Exception {
+        OkHttpClient okClient = Mockito.mock(OkHttpClient.class);
+        okhttp3.Response response = Mockito.mock(okhttp3.Response.class);
+        Call call = Mockito.mock(Call.class);
+
+        doReturn(call).when(okClient).newCall(any());
+
+        doAnswer(invocation -> {
+            ((Callback) invocation.getArgument(0)).onResponse(call, response);
+            return null;
+        }).when(call).enqueue(any(Callback.class));
+
+        Headers headers = Mockito.mock(Headers.class);
+        when(response.headers()).thenReturn(headers);
+
+        DefaultHttpClient client = new DefaultHttpClient(okClient);
+        Auth0HttpRequest request = Auth0HttpRequest.newBuilder(server.url("/users/").toString(), HttpMethod.POST)
+            .withBody(HttpRequestBody.create("application/json", "{}".getBytes()))
+            .build();
+
+        MockResponse mockResponse = new MockResponse()
+            .setResponseCode(500)
+            .setBody("server error");
+
+        server.enqueue(mockResponse);
+        client.sendRequestAsync(request).get();
+        verify(response, times(1)).close();
+    }
+
     @Test
     public void makesFormBodyPostRequest() throws Exception {
         Map<String, Object> params = new HashMap<>();