reactfx/src/main/java/org/reactfx/EventStream.java
default EventStream<T> reduceBetween(
            EventStream<?> ticks,
            BinaryOperator<T> reduction) {
        return accumulateBetween(
                ticks,
                Function.identity(),
                reduction,
                Collections::singletonList);
    }
/**
     * Returns an event stream that, when an event arrives from this stream,
     * stores it for emission. Any further events that arrive from this stream
     * are reduced into the stored event using the {@code reduction} function.
     * The stored event is emitted from the returned stream when a <i>tick</i>
     * arrives from the {@code ticks} stream.
     *
     * <p>Note that {@code retainLatestBetween(ticks)} is equivalent to
     * {@code reduceBetween(ticks, (a, b) -> b)}.
     */
Returns an event stream that, when an event arrives from this stream,
stores it for emission. Any further events that arrive from this stream
are reduced into the stored event using the  reduction function.
The stored event is emitted from the returned stream when a tick
arrives from the  ticks stream.

Note that  retainLatestBetween(ticks) is equivalent to
reduceBetween(ticks, (a, b) -> b).
Returns an event stream that when an event arrives from this stream stores it for emission . Any further events that arrive from this stream are reduced into the stored event using the reduction function . The stored event is emitted from the returned stream when a tick arrives from the ticks stream . Note that retainLatestBetween ( ticks ) is equivalent to reduceBetween ( ticks ( a b ) - > b ) .
default EventStream<T> reduceBetween(
            EventStream<?> ticks,
            BinaryOperator<T> reduction) {
        return accumulateBetween(
                ticks,
                Function.identity(),
                reduction,
                Collections::singletonList);
    }
default EventStream < T > reduceBetween ( EventStream < ? > ticks , BinaryOperator < T > reduction ) { return accumulateBetween ( ticks , Function . identity ( ) , reduction , Collections :: singletonList ) ; }
Returns an event stream that, when an event arrives from this stream,
 stores it for emission.
Returns an event stream that when an event arrives from this stream stores it for emission .