@Override
  public void loadData(Priority priority, DataCallback<? super T> callback) {
    this.callback = callback;
    serializer.startRequest(priority, url, this);
  }
@Test
  public void testLoadData_createsAndStartsRequest() {
    when(cronetRequestFactory.newRequest(
            eq(glideUrl.toStringUrl()),
            eq(UrlRequest.Builder.REQUEST_PRIORITY_LOWEST),
            anyHeaders(),
            any(UrlRequest.Callback.class)))
        .thenReturn(builder);

    fetcher.loadData(Priority.LOW, callback);

    verify(request).start();
  }