Most reliable way to check if a FormAction just started

Hi, within a FormAction I often want to know if its the very first turn within this FormAction. However, Im not sure if theres a reliable way to check.

Ways I know and their disadvantages.

a) Check if requested_slot is None

  • slot might be set by another (Form)Action before.

b) Check if tracker.active_form is an empty dict

  • doesnt work if a Form triggers another Form (may not be very likely)

Do you know other ways?