code: public static RequestToken delete(String collection, String id, int flags, BaasHandler<Void> handler) {
          BaasBox box = BaasBox.getDefaultChecked();
          if (collection == null) throw new IllegalArgumentException("collection cannot be null");
          if (id == null) throw new IllegalArgumentException("id cannot be null");
          Delete delete = new Delete(box, collection, id, flags, handler);
          return box.submitAsync(delete);
      }
docs: Asynchronously deletes the document with {@code id} from {@code collection}
  @param collection the collection of the document
  @param id the id of the document
  @param flags {@link RequestOptions}
  @param handler a callback to be invoked with the result of the request
  @return a {@link com.baasbox.android.RequestToken} to handle the asynchronous request