code: List<HttpSenderListener> getHttpSenderListeners() {
          if (httpSenderListeners == null) {
              return Collections.emptyList();
          }
          return Collections.unmodifiableList(httpSenderListeners);
      }
docs: Gets the {@link HttpSenderListener}s added to this hook.
  
  @return an unmodifiable {@code List} containing the added {@code HttpSenderListener}s, never {@code null}.
  @since 2.7.0