function getCandidate() {
            var nextItem;
            this._queue.each(function(item) {
                if (item.state === Queueable.IDLE || item.state === Queueable.RESUMED) {
                    nextItem = item;
                    return false;
                }
            });
            return nextItem;
        }
Removes item from the queue and destroys it

@method removeItem
@param {String} uid