(PECL zmq >= 0.5.0) Count items in the poll set

(PECL zmq >= 0.5.0) Poll the items public

(PECL zmq >= 0.5.0) Remove item from poll set

(PECL zmq >= 0.5.0) Get poll errors public

(PECL zmq >= 0.5.0) Add item to the poll set

(PECL zmq >= 0.5.0) Clear the poll set public