Allow the use of element properties that are backed by some iterator. For example, an integer property with a SummingCombiner in the "background", so that when the property is "set", the value actually gets incremented. Retrieving the property will get back the current sum.
Allow the use of element properties that are backed by some iterator. For example, an integer property with a SummingCombiner in the "background", so that when the property is "set", the value actually gets incremented. Retrieving the property will get back the current sum.