code: function (name, cb, lazy) {
              if (!lazy && name in triggerCache) {
                  cb(triggerCache[name]);
              }
              events[name] = events[name] || [];
              events[name].push(cb);
          }
docs: ## handler.on(name, callback, [lazy])
  Bind a callback to an event. Callback will run each
  time the event is triggered.
  @param {string} name Event name.
  @param {function(?)} cb Event callback.
  @param {boolean} [lazy] True if this callback should not fire
  immediately if the event has already been triggered.