@Override public CompletableFuture<Optional<T>> max(final Comparator<? super T> comparator){
  return CompletableFuture.supplyAsync(null,exec);
}

@ Override public CompletableFuture < Optional < T > > max ( final Comparator < ? super T > comparator ) { return CompletableFuture . supplyAsync ( null , exec ) ; }
perform an asyncrhonous min operation
