src/Google/Task/Runner.php
public function attempt()
  {
    if (!$this->canAttempt()) {
      return false;
    }

    if ($this->attempts > 0) {
      $this->backOff();
    }

    $this->attempts++;
    return true;
  }
public function attempt()
  {
    if (!$this->canAttempt()) {
      return false;
    }

    if ($this->attempts > 0) {
      $this->backOff();
    }

    $this->attempts++;
    return true;
  }
Runs a task once, if possible. This is useful for bypassing the `run()`
loop.

NOTE: If this is not the first attempt, this function will sleep in
accordance to the backoff configurations before running the task.

@return boolean