For implementers, the locking model adds a fair amount of non-trivial internal bookkeeping. Every operation must check lock state, readers must be tracked, and the interplay between locks, cancellation, and error states creates a matrix of edge cases that must all be handled correctly.
第一盏灯：位置在左上方 (-1, 2, 4)，负责照亮物体的正面。
。体育直播对此有专业解读
For multiple readers
-ef # alternate spelling