fold
inline fun <ID : Any, R> Field<ID, *>.foldIDs(initial: R, crossinline accumulator: Accumulator<R, ID>): R
Accumulates a result starting from initial, by applying accumulator to each ID in the field (excluding the local one).
This is a convenience fold that operates only on field entry IDs.
Return
the final accumulated result.
Parameters
initial
the initial value for the accumulation.
accumulator
the function that combines the current accumulator value with each entry's ID.