What is that PoC in the issue doing? They check e which is not set after first line in the function:

    func send(addr, server, sni string) int {
     c0, e := net.Dial("tcp", addr)
     if e != nil {
      log.Fatal(e)
     }
    
     c1 := tls.Client(c0, &tls.Config{
      ServerName:         server,
      InsecureSkipVerify: true,
     })
    
     c2 := tls.Client(c1, &tls.Config{
      ServerName:         sni,
      InsecureSkipVerify: true,
     })
     c2.SetDeadline(time.Now().Add(2 * time.Minute))
     s := fmt.Sprintf("GET / HTTP/1.1\r\nHost: %s\r\nUser-Agent: curl/7.68.0\r\n\r\n", sni)
     //b := make([]byte, 4096)
     l, _ := c2.Write([]byte(s))
     log.Println(l)
     if e != nil {
      return 0
     }
     log.Printf("%s->%s->%s\n", addr, server, sni)
     return l
    }