(PECL gearman >= 0.5.0)
GearmanClient::setCompleteCallback — Set a function to be called on task completion
Use to set a function to be called when a task is completed. The callback function should accept a single argument, a GearmanTask object.
callback
A function to be called
성공 시 TRUE
를, 실패 시 FALSE
를 반환합니다.