*
       * Example:
       * ```
       * --> POST /greeting http/1.1
       * Host: example.com
       * Content-Type: plain/text
       * Content-Length: 3
       *
       * Hi?
       * --> END POST
       *
       * <-- 200 OK (22ms)
       * Content-Type: plain/text
       * Content-Length: 6
       *
       * Hello!
       * <-- END HTTP
       * ```
       */