notifiee.go
func (nb *NotifyBundle) ClosedStream(n Network, s Stream) {
	if nb.ClosedStreamF != nil {
		nb.ClosedStreamF(n, s)
	}
}
func (nb *NotifyBundle) ClosedStream(n Network, s Stream) {
	if nb.ClosedStreamF != nil {
		nb.ClosedStreamF(n, s)
	}
}
// ClosedStream calls ClosedStreamF if it is not null.