function flush() {
        return timerId === undefined ? result : trailingEdge(now());
      }
Defers invoking the `func` until the current call stack has cleared. Any
additional arguments are provided to `func` when it's invoked.

@static
@memberOf _
@since 0.1.0
@category Function
@param {Function} func The function to defer.
@param {...*} [args] The arguments to invoke `func` with.
@returns {number} Returns the timer id.
@example

_.defer(function(text) {
  console.log(text);
}, 'deferred');
// => Logs 'deferred' after one millisecond.