它实现了协程同步事件、协程锁、协程池、channel、waitgroup，内存占用少实测 1000 万协程占用 2.8G 内存。 ```c++ #include "co/co.h" DEF_main(argc, argv) { co::Chan<int> ch; go([ch]() { /* capture by value, rather than reference */ ch << 7; }); int v = 0; ch >> v; LOG << "v: " << v; return 0; } ```