In commercial irrigation timers this feature is called “learn flow” it is ran once when the system is free of breaks and dialed in, values are stored in a per station basis and used as a starting point then a % treshold is set because we wont get the exact seme result every time we run the system. I have also been waiting and requesting this feature for a very long time. This would be the only way to go to the next step where notifications can be set for no flow, low flow, high flow, if no stations are running and there is flow then it would be a broken main line and an action can be taken if a master valve is installed kike shutting the water off of save tons of water.