Disable Keep-Alive to save battery

[fortuna]

Intra should disable Keep-Alive to avoid waking up the network device when not needed.

The dialer is created at

Intra/Android/app/src/go/intra/protect/protect.go

Line 95 in ede31e6

func MakeDialer(p Protector) *net.Dialer {

In

Intra/Android/app/src/go/intra/protect/protect.go

Line 108 in ede31e6

return d.DialContext(ctx, network, newAddress)

we should check if the connection is a TCPConn, and disable the Keep Alive with https://pkg.go.dev/net#TCPConn.SetKeepAlive.

[fortuna]

For context, see Jigsaw-Code/outline-ss-server#108.

Without disabling the Keep-Alive, it pings the peer every 15 seconds!