Atomic registration: wait_for checks the current value and registers the queue inside the same lock acquisition, closing the race where a transition could slip between registration and the initial check.
lineage_xigua.mk :: defines a module, which actually defines the device
，更多细节参见同城约会
next empty line. Finally, the 3618 was a "medium-speed" printer, meaning 155 lines per minute.
Every unit of work makes subsequent work easier. Code, documentation, and tooling should build on each other and make future work faster, not slower.