code: public static Func1<Iterable<Long>, long[]> toLongs() {
          return new Func1<Iterable<Long>, long[]>() {
              @Override
              public long[] call(Iterable<Long> value) {
                  return new QuickNumberArray(value).toLongs();
              }
          };
      }
docs: Returns a method that can be used with {@link solid.stream.Stream#collect(Func1)}
  to convert an iterable stream of {@link Number} type into a primitive long[] array.
  
  @return a method that converts an iterable stream of {@link Number} type into a primitive long[] array.