@Override public <R,A>CompletableFuture<R> collect(final Collector<? super T,A,R> collector){
  return CompletableFuture.supplyAsync(null);
}

@ Override public < R , A > CompletableFuture < R > collect ( final Collector < ? super T , A , R > collector ) { return CompletableFuture . supplyAsync ( null ) ; }
asynchronously perform a stream collection
