code: public static <T> StreamEx<T> constant(T value, long length) {
          return of(new ConstSpliterator.OfRef<>(value, length, false));
      }
docs: Returns a sequential unordered {@code StreamEx} of given length which
  elements are equal to supplied value.
  
  @param <T> the type of stream elements
  @param value the constant value
  @param length the length of the stream
  @return a new {@code StreamEx}
  @since 0.1.2