[belak]

You'd be surprised. Go actually has a supported SSH library which is a fairly decent protocol-level implementation. To actually get a "shell server" you would need to implement handling of SSH sessions (as described in the RFCs) but all the low level stuff is taken care of.

EDIT: As an example, the gogs project has implemented a small ssh server so people running it don't need to hook into OpenSSH, which relies on specific versions of OpenSSH to be performant. See https://github.com/gogits/gogs/blob/master/modules/ssh/ssh.g...