(PECL event >= 1.2.6-beta)
EventBuffer::unfreeze — Re-enable calls that modify an event buffer
$at_front
): boolRe-enable calls that modify an event buffer.
at_front
Whether to enable events at the front or at the end of the buffer.
成功時(shí)返回 true， 或者在失敗時(shí)返回 false。