close(connClosed)
		return nil
	}

	inWrite := make(chan bool, 1)
	var errConnClosed = errors.New("conn closed for test")
	conn.writeFunc = func(p []byte) (n int, err error) {
		inWrite <- true
		<-connClosed
		return 0, errConnClosed
	}

	closeReturned := make(chan bool, 1)
	go func() {
		<-inWrite
		tconn.Close() // test that this doesn't block forever.
		closeReturned <- true