[Showcase PR] ShadowSocks patch to prove the ability of seamless update

[erikziyunchi]

Earlier this year, China has started to block fully encrypted protocols, and @gfw-report has published a patch for modifying SS to mitigate this problem.

This PR is a showcase where how easy and seamless this patch can be implemented in W.A.T.E.R. just like patching on the official shadowsocks_rust.

[erikziyunchi]

Probably leave lint as it, since those are the exact changes from the patch where we want to show that no additional work needed in our implementation.

[gaukas]

If it breaks lint, I think we'd better keep it in a separate branch for now. This will fulfills our purpose of showing the patch without making the major parts of our repo seem broken.

[erikziyunchi]

Yeah, this is what I was thinking as well. Since it will also be hard to test where we need to spawn a local ShadowSocks server with the corresponding patch to make it encrypt & decrypt correctly.

[erikziyunchi]

This is a showcase PR which demonstrate the same patch for shadowsocks-rust can be applied to WATER will not be merged. For more details look at the first comment.