@Override default CompletableFuture<OptionalLong> minLong(final ToLongFunction<? super T> fn){
  return CompletableFuture.supplyAsync(null,getExec());
}

@ Override default CompletableFuture < OptionalLong > minLong ( final ToLongFunction < ? super T > fn ) { return CompletableFuture . supplyAsync ( null , getExec ( ) ) ; }
perform an asynchronous min operation
