code: public <T> T getState(HttpConnectionInterceptor interceptor, String stateName, Class<T>
              stateType) {
          Map<String, Object> state = interceptorStates.get(interceptor);
          if (state != null) {
              return stateType.cast(state.get(stateName));
          } else {
              return null;
          }
      }
docs: Retrieve the state object associated with the specified interceptor instance and property
  name on this request context.
  
  @param interceptor the interceptor instance
  @param stateName   the name key that the state object was stored under
  @param stateType   class of the type the stored state should be returned as
  @param <T>         the type the stored state should be returned as
  @return the stored state object
  @see #setState(HttpConnectionInterceptor, String, Object)
  @since 2.6.0