#!/bin/bash

sleep 1
echo "sync_barrier_start"
nc -v --udp --source 127.0.0.1 --source-port $1 127.13.3.7 $2 --sh-exec '(while true; do sleep 1; echo a; done) & B=$!; read r; kill $B'
echo "sync_barrier_release"
sleep 10
echo "sync_barrier_done"