A Golang TLV example
https://levelup.gitconnected.com/binary-encoding-of-variable-length-options-with-golang-4481ff59e767
Server
$ go run main.go
2021/09/09 10:33:51 Listening tcp://127.0.0.1:8081...
Client
$ echo -e '\x00\x08\x00\x0a\x68\x65\x6c\x6c\x6f\x2c\x20\x67\x6f\x21' | nc -c 127.0.0.1 8081
Server's output:
2021/09/09 10:33:54 type: 8
2021/09/09 10:33:54 payload: hello, go!