http 長連接及httpclient連接池

http長連接 https://www.cnblogs.com/kingszelda/p/8988505.html

httpclient 連接池 https://www.jianshu.com/p/363e3d7c235b

https://www.jianshu.com/p/187dde35336d

https://www.jianshu.com/p/375be5929bed