etcdserver/util.go
func isConnectedSince(transport rafthttp.Transporter, since time.Time, remote types.ID) bool {
	t := transport.ActiveSince(remote)
	return !t.IsZero() && t.Before(since)
}
func isConnectedSince(transport rafthttp.Transporter, since time.Time, remote types.ID) bool {
	t := transport.ActiveSince(remote)
	return !t.IsZero() && t.Before(since)
}
// isConnectedSince checks whether the local member is connected to the
// remote member since the given time.