code: func Peek(xu *xgbutil.XUtil) []xgbutil.EventOrError {
  	xu.EvqueueLck.RLock()
  	defer xu.EvqueueLck.RUnlock()
  
  	cpy := make([]xgbutil.EventOrError, len(xu.Evqueue))
  	copy(cpy, xu.Evqueue)
  	return cpy
  }
docs: // Peek returns a *copy* of the current queue so we can examine it.
  // This can be useful when trying to determine if a particular kind of
  // event will be processed in the future.