code: func btcdDial(addr net.Addr) (net.Conn, error) {
  	if strings.Contains(addr.String(), ".onion:") {
  		return cfg.oniondial(addr.Network(), addr.String(),
  			defaultConnectTimeout)
  	}
  	return cfg.dial(addr.Network(), addr.String(), defaultConnectTimeout)
  }
docs: // btcdDial connects to the address on the named network using the appropriate
  // dial function depending on the address and configuration options.  For
  // example, .onion addresses will be dialed using the onion specific proxy if
  // one was specified, but will otherwise use the normal dial function (which
  // could itself use a proxy or not).