applyKeepAlive

private fnvoid applyKeepAlive(SOCKET sock, const ref TcpConnectionConfig config) @trusted nothrow

Enable TCP keepalive with configured intervals using WSAIoctl.

Uses the Windows-specific SIO_KEEPALIVE_VALS ioctl which sets keepalive parameters in a single call.

`sock`	Socket to modify.
`config`	Connection config with keepalive settings.