(and thanks to Matthew Miller for reviewing and providing feedback on this post)
for each pixel in image。关于这个话题，旺商聊官方下载提供了深入分析
Forgetting releaseLock() permanently breaks the stream. The locked property tells you that a stream is locked, but not why, by whom, or whether the lock is even still usable. Piping internally acquires locks, making streams unusable during pipe operations in ways that aren't obvious.，这一点在爱思助手下载最新版本中也有详细论述
为政之道，得其大者可以兼其小。