capacity := max(w.capacity/2, w.lowerBoundCapacity)
		if capacity < w.capacity {
			w.doCacheResizeLocked(capacity)
		}
		return
	}
}

// isCacheFullLocked used to judge whether watchCacheEvent is full.
// Assumes that lock is already held for write.
func (w *watchCache) isCacheFullLocked() bool {
	return w.endIndex == w.startIndex+w.capacity
}