Temporal Activity does not pass Parameters with json:"-"

Hi all,
I have an activity that sends a request body using REST API:

My TempRequest has 3 params: trxId, channel, and request.

trxId is not meant to be sent in the request body, but it is mapped in header and/or query parameter of the http request, that’s why it has json:"-". It is used inside adapter.UpdateStatus() (line 60).

Before calling workflow.ExecuteActivity(), I print the request, and trxId has value:

But when I print from inside the activity, it is gone:

Does it mean that when passing request to activity, there is some kind of marshalling and unmarshalling?

Yes, all activity executions are part of the workflow event history and are sent to the Temporal server serialized where the temporal server can request a worker pick up the activity execution.