docs: public void trackLoading(boolean lastBatch, Throwable exception) {
          if (lastBatch) {
              state.nextOrStay(State.LOADED);
              if (exception != null) {
                  keyLoadFinished.setResult(exception);
              } else {
                  keyLoadFinished.setResult(true);
              }
          } else if (state.is(State.LOADED)) {
              state.next(State.LOADING);
          }
      }