text: var events = require('events');
  
  if(typeof events.EventEmitter.prototype.once !== 'function') {
    events.EventEmitter.prototype.once = function (type, listener) {
      var self = this;
      self.on(type, function g () {
        self.removeListener(type, g);
        listener.apply(this, arguments);
      });
    };
  }
  