func (k *ktester) get(mr kex2.MessageRouter, low kex2.Seqno, poll time.Duration) ([][]byte, error) {
	return mr.Get(k.I, k.receiver, low, poll)
}
func (k *ktester) post(mr kex2.MessageRouter, b []byte) error {
	k.seqno++
	return mr.Post(k.I, k.sender, k.seqno, b)
}