wrapTimeout: function(promise, callback) {
    if (callback) {
      // Ensure callback is called outside of promise stack.
      return promise.then(
        function(res) {
          callback(null, res);
          // setTimeout(function() { callback(null, res) }, 0);
        },
        function(err) {
          callback(err, null);
          // setTimeout(function() { callback(err, null); }, 0);
        }
      );
    }