Channel = function(type, sticky) {
              this.type = type;
              // Map of guid -> function.
              this.handlers = {};
              // 0 = Non-sticky, 1 = Sticky non-fired, 2 = Sticky fired.
              this.state = sticky ? 1 : 0;
              // Used in sticky mode to remember args passed to fire().
              this.fireArgs = null;
              // Used by onHasSubscribersChange to know if there are any listeners.
              this.numHandlers = 0;
              // Function that is called when the first listener is subscribed, or when
              // the last listener is unsubscribed.
              this.onHasSubscribersChange = null;
          }
Channel
@constructor
@param type  String the channel name