参考文章：https://blog.csdn.net/alwaysrun/article/details/89076492 https://www.jianshu.com/p/fd0a624d0912 https://cloud.tencent.com/developer/article/1928677文档：https://www.rfc-editor.org/rfc/rfc6347  https://www.rfc-editor.org/rfc/rfc52461.SSL/TL