Sensor device class for volumes and flows

I would like a device class for sensors that are measuring volume and flow.
This is to be used for representing a water meter, with the correct units of measurement.

+1

as m³/h, m³/m, m³/s, same for l and as a percentage.

And another +1! Flow and volume would be really helpful for readings coming out of heat meters.

+1, water flow in Gallons Per Minute (GPM) should be available. Is it that uncommon to have a water flow sensor?

yes yes, water flow as in l/h (liters per hour) for heat meters (district heating)! Might as well add GJ (GigaJoules)

With heat pumps becoming much more mainstream, this device class will become used a lot more. It seems to be a pretty trivial addition from what I can see. What needs to be doe to get more visibility of this?

Yes please, noticed I get warnings when using water or gas device class with measurement state, need a flow rate device class.

For instant water heating devices a flow with l/min would be helpful too.

Coming soon: Add volume_flow_rate device class · home-assistant/architecture · Discussion #915 (github.com).

device_class: volume_flow_rate