Function: `QueryReduce`

This function reduces the query to a single value.

Method Signature

QueryReduce(query=[query], callback=[function:BiFunction], initialValue=[any])

Argument	Type	Required	Description
`query`	`query`	`true`	The query to iterate over
`callback`	`function:BiFunction`	`true`	The function to invoke for each item. The function will be passed 4 arguments: the accumulator, the current item, the current index, and the query. You can alternatively pass a Java Predicate which will only receive the first 2 args.
`initialValue`	`any`	`true`	The initial value to use for the reduction