并发（concurrency）, 并行（parallelism）

并行指物理上同时执行，并发指能够让多个任务在逻辑上交织执行的程序设计

https://www.cnblogs.com/f-ck-need-u/p/11161481.html

https://laike9m.com/blog/huan-zai-yi-huo-bing-fa-he-bing-xing,61/

https://blog.golang.org/concurrency-is-not-parallelism

https://talks.golang.org/2012/waza.slide#1