(PECL libevent >= 0.0.4)
event_buffer_set_callback — Set or reset callbacks for a buffered event
Sets or changes existing callbacks for the buffered event.
Valid buffered event resource.
Callback to invoke where there is data to read, or NULL if no callback is desired.
Callback to invoke where the descriptor is ready for writing, or NULL if no callback is desired.
Callback to invoke where there is an error on the descriptor, cannot be NULL .
An argument that will be passed to each of the callbacks (optional).
成功した場合に TRUE を、失敗した場合に FALSE を返します。