Type Alias MeteringFactory 

pub type MeteringFactory = Box<dyn FnOnce(&MeteringInit<'_>) -> Result<Option<Arc<dyn Metering>>, String> + Send>;

Deployment hook: build the metering implementation once models are loaded. Ok(None) = no accounting (the stock no-ledger shape). An Err is a startup FATAL — accounting configuration never fails open.

Aliased Type

pub struct MeteringFactory(/* private fields */);