The documentation for the GA4 measurement protocol only describes sending events, and notes that the key events for measuring session duration etc. are reserved (automatically provided by gtag/firebase).
I'm attempting to use the measurement protocol in a .NET desktop environment (not firebase/web/android/ios). Sending events works as expected (they show up on the dashboard), but the user count always shows as zero. Sending a session_started event to the debug endpoint does not pass validation (states that it is a reserved event name).
Is it possible to manually send the events required to track sessions or is there another way to get an accurate user count without using firebase/gtag?
Protocol reference: https://developers.google.com/analytics/devguides/collection/protocol/ga4