http://blog.dyngr.com/blog/2016/09/15/java-forkjoinpool-internals/
http://colobu.com/2016/02/29/Java-CompletableFuture/
Java 多线程中的任务分解机制-ForkJoinPool
原文：https://www.cnblogs.com/hongdada/p/8876028.html
