packet-generator new {
  name x
  limit 1
  node ip4-input
  size 50-50
  data {
    ICMP: 1.2.3.4 -> 5.6.7.8
    ICMP echo_request
    incrementing 100
  }
}

tr add pg-input 100
ip route 5.6.7.8/32 via pg/stream-0 000102030405060708090a0b0c0d