telephonySessionId is the value that the API RingOut return to the client after a success outbound call is originated. And this is also the unique key across multiple Webhook events related to a single call. This is the only info that the client application know about the call, so accessing the Call Record Detail using this telephonySessionId is a must have feature because filtering this value using the API List User Call Records will slower that getting the record detail directly using API Get User Call Record.

I hope you can make the API Get User Call Record accept telephonySessionId as the identifier for the call and return data exactly like when we use the internal call id. It will help to save the effort at the client side and save the server performance at the API server side as well.