nettrace

type LookupIPAltResolverKey struct{}

type Trace struct {
	// DNSStart is called with the hostname of a DNS lookup
	// before it begins.
	DNSStart func(name string)

	// DNSDone is called after a DNS lookup completes (or fails).
	// The coalesced parameter is whether singleflight de-duped
	// the call. The addrs are of type net.IPAddr but can't
	// actually be for circular dependency reasons.
	DNSDone func(netIPs []any, coalesced bool, err error)

	// ConnectStart is called before a Dial, excluding Dials made
	// during DNS lookups. In the case of DualStack (Happy Eyeballs)
	// dialing, this may be called multiple times, from multiple
	// goroutines.
	ConnectStart func(network, addr string)

	// ConnectStart is called after a Dial with the results, excluding
	// Dials made during DNS lookups. It may also be called multiple
	// times, like ConnectStart.
	ConnectDone func(network, addr string, err error)
}

type TraceKey struct{}