What is the idiomatic way in Go to timeout a TCP conversation, such as initial protocol handshake? Let's say there is a goroutine that handles the TCP conversation. I can launch it, then launch a time.After(), then select for both of them and if timeout was hit, proceed on doing other stuff.
However, that means that the TCP goroutine will linger on after the timeout keeping the TCP connection alive even though nobody will ever need it.
To timeout the initial connection, you use net.DialTimeout, or more specifically, set the Timeout parameter on a net.Dialer.
To timeout individual operations on a TCP connection while it's in use, you use SetDeadline, SetReadDeadline, or SetWriteDeadline on the connection.
If you need to cancel operations on a connection immediately, the way to do that in Go is to Close() the connection. Connections are safe for concurrent operations, and you can call Close() from a goroutine other than the one blocking on the network operation.