docs: public BoxFutureTask<BoxSession> refresh() {
          if (mRefreshTask != null && mRefreshTask.get() != null){
              BoxFutureTask<BoxSession> lastRefreshTask = mRefreshTask.get();
              if (!(lastRefreshTask.isCancelled() || lastRefreshTask.isDone())){
                  return lastRefreshTask;
              }
          }
          final BoxFutureTask<BoxSession> task = (new BoxSessionRefreshRequest(this)).toTask();
          new Thread(){
              @Override
              public void run() {
                  task.run();
              }
          }.start();
          mRefreshTask = new WeakReference<BoxFutureTask<BoxSession>>(task);
          return task;
      }