(PECL gearman >= 0.6.0)
GearmanJob::sendFail — Send fail status
Sends failure status for this job, indicating that the job failed in a known way (as opposed to failing due to a thrown exception).
此函數沒(méi)有參數。
成功時(shí)返回 true， 或者在失敗時(shí)返回 false。