Change underlying protocol on UDP

[tsuzu]

utp, a library which is used by go-easyp2p is deprecated.(anacrolix/utp#26)
Therefore, we should use another library.

There are some candidates

• quic-go
• go-libutp

However, all of these have problems.

quic-go

• QUIC, which is a protocol used by quic-go is experimental.
• The architecture of QUIC is stream-multiplexing, so if I adopt it, APIs of go-easyp2p will have to be changed largely.

go-libutp

• go-libutp depends on libutp, which is written in C/C++, so it will get more difficult to cross-compile programs using go-easyp2p.

I considered whether kcp-go can be used, but it doesn't implement control messages such as SYN/FIN/RST, so I think it's very difficult to adopt it.

If you know other libraries, please tell me them.

[tsuzu]

FIx in 66b9797

[jannson]

You can use "kcp-go" + "smux" .

[tsuzu]

Yes!
I like "kcp-go" and "smux" very much, (I use "smux" in cs3238-tsuzu/ftrans.) but I used QUIC because it is being standardized.

[anacrolix]

Has anacrolix/utp worked all right for you so far?

[tsuzu]

@anacrolix Yes. It worked perfectly. Thank you so much!