code: func Poll(interval, timeout time.Duration, condition ConditionFunc) error {
  	return pollInternal(poller(interval, timeout), condition)
  }
docs: // Poll tries a condition func until it returns true, an error, or the timeout
  // is reached.
  //
  // Poll always waits the interval before the run of 'condition'.
  // 'condition' will always be invoked at least once.
  //
  // Some intervals may be missed if the condition takes too long or the time
  // window is too short.
  //
  // If you want to Poll something forever, see PollInfinite.