notifiee.go
func (nb *NotifyBundle) Disconnected(n Network, c Conn) {
	if nb.DisconnectedF != nil {
		nb.DisconnectedF(n, c)
	}
}
func (nb *NotifyBundle) Disconnected(n Network, c Conn) {
	if nb.DisconnectedF != nil {
		nb.DisconnectedF(n, c)
	}
}
// Disconnected calls DisconnectedF if it is not null.