params='-hostname=me.example.org -logger=postfix-in -pid=1234'
while true; do
  for msg in \
      'connect from somehost.example.org[10.1.2.3]' \
      '12345678: client=somehost.example.org[10.1.2.3]' \
      '12345678: message-id=<20150709142617.12345678@me.example.org>' \
      '12345678: from=<no-reply@app.example.org>, size=1289, nrcpt=1 (queue active)' \
      '12345678: to=<someuser@example.org>, relay=smarthost.example.org[10.2.3.4]:25, delay=0.29, delays=0.05/0/0.04/0.2, dsn=2.6.0, status=sent (250 2.6.0 <20150709142617.12345678@me.example.org> [InternalId=5678] Queued mail for delivery)' \
      '12345678: removed' \
      'disconnect from somehost.example.org[10.1.2.3]'; do
    heka-inject $params -payload="$msg"
    sleep 2
  done
done

# Expected output:
Fields:
 connect_from_host=somehost.example.org
 connect_from_ip=10.1.2.3
 client_host=somehost.example.org
 client_ip=10.1.2.3
 message_id=20150709142617.12345678@me.example.org
 from=no-reply@app.example.org
 size=1289
 nrcpt=1
 to=someuser@example.org
 relay_host=smarthost.example.org
 relay_ip=10.2.3.4
 relay_port=25
 ...