message: refactor: use better merge from vue source to merge handlers
diff: @@ -107,27 +107,10 @@ export function addVNodeListener(vnode: VNode, eventName: string, handler: Funct
  vnode.props = {};
  }
  - if (!vnode.props[eventPropName]) {
  - vnode.props[eventPropName] = handler;
  - return;
  + const existing = vnode.props[eventPropName];
  + if (existing !== handler) {
  + vnode.props[eventPropName] = existing ? [].concat(existing as any, handler as any) : handler;
  }
  -
  - if (vnode.props[eventPropName] === handler) {
  - return;
  - }
  -
  - const evtObj = vnode.props[eventPropName];
  - if (Array.isArray(evtObj) && evtObj.indexOf(handler) === -1) {
  - evtObj.push(handler);
  - return;
  - }
  -
  - if (typeof evtObj === 'function') {
  - vnode.props[eventPropName] = [evtObj, handler];
  - return;
  - }
  -
  - console.log('Cannot handle this evt obj!', evtObj);
  }
  // Determines if `change` should be used over `input` for listeners.
  