The success path in handleResult left settled at 0, so drainLoser
waited on a result that was already consumed and blocked forever,
leaking a goroutine and the results channel on every successful race.
Increment settled before stop() so drainLoser only waits for actual
started losers.
handleResult returned (net.Conn, error, bool) and produced (nil, nil, false)
on the non-terminal path, which the nilnil linter rejects. Return a
raceOutcome{conn, err, done} struct instead so the not-done case carries no
ambiguous nil value / nil error pair.
Rename the ConnRacer type to FallbackOpener and its constructor to
NewFallbackOpener. Rename fallback.go to fallback_opener.go and
foreign_relays.go to foreign_relays_store.go so file names mirror their
primary struct.
Zoltan Papp