Jjjpan

In a test case of many subscribe and many subscribeOnce, bus.removeHandler tries to remove a handler with index out of range. Add out-of-range outputs in `event_bus.go`: ``` func (bus *EventBus)...

Would it be better to use `offset` to record the offset of index between `handlers` and `copyHandlers`.🙄 Maybe like this: ``` func (bus *EventBus) Publish(topic string, args ...interface{}) { bus.lock.Lock()...