usecrate::aggregate::AggregateOp;/// An [`AggregateOp`] that can also operates on a mutable reference to an item.
pubtraitRefAggregateOp: AggregateOp {/// Creates a new value for a newly created group.
////// See [`AggregateOp::new_value()`] for more detail.
fnnew_value_ref(&mutself, key:&Self::Key, item:&mutSelf::Item)->Self::Value;/// Creates a new value for a newly created group.
////// See [`AggregateOp::modify()`] for more detail.
fnmodify_ref(&mutself, value:&mutSelf::Value, item:&mutSelf::Item);}