code: function() {
          if (AV._config.disableCurrentUser) {
            console.warn(
              'AV.User.current() was disabled in multi-user environment, call logOut() from user object instead https://leancloud.cn/docs/leanengine-node-sdk-upgrade-1.html'
            );
            return Promise.resolve(null);
          }
  
          if (AV.User._currentUser !== null) {
            AV.User._currentUser._logOutWithAll();
            AV.User._currentUser._isCurrentUser = false;
          }
          AV.User._currentUserMatchesDisk = true;
          AV.User._currentUser = null;
          return AV.localStorage
            .removeItemAsync(AV._getAVPath(AV.User._CURRENT_USER_KEY))
            .then(() => AV._refreshSubscriptionId());
        }
docs: Logs out the currently logged in user session. This will remove the
  session from disk, log out of linked services, and future calls to
  <code>current</code> will return <code>null</code>.
  @return {Promise}