code: public void cancelAll(final Object tag) {
          if (tag == null) {
              throw new IllegalArgumentException("Cannot cancelAll with a null tag");
          }
          cancelAll(new RequestFilter() {
              @Override
              public boolean apply(Request<?> request) {
                  return request.getTag() == tag;
              }
          });
      }
docs: Cancels all requests in this queue with the given tag. Tag must be non-null
  and equality is by identity.