Real time trip update for ferry

Hi There,
Why I cannot get the trip update ferry any component below stop_time_update node?
I can do a get action to see that, but I cannot do a post through my c# app, nothing under stop_time_update node! Please help me!
Thanks in advance!

stop_time_update {
stop_sequence: 1
arrival {
delay: 0
departure {
delay: 198
stop_id: “20006”
schedule_relationship: SCHEDULED

Hi guys,

The real question is under trip_update.stop_time_update. There are no delay node can be found!
Any idea? And libraries I need to call?
Thanks in advance!