static <T1,T2>Seq<Tuple2<T1,T2>> combineLatest(final SimpleReactStream<T1> left,final SimpleReactStream<T2> right){
  return combineLatest(left,right,null);
}

static < T1 , T2 > Seq < Tuple2 < T1 , T2 > > combineLatest ( final SimpleReactStream < T1 > left , final SimpleReactStream < T2 > right ) { return combineLatest ( left , right , null ) ; }
zip two streams into one . uses the latest values from each rather than waiting for both
