@Override
    public String toString() {
        ToStringHelper helper = MoreObjects.toStringHelper("byte[]");
        if (bytes != null) {
            helper.add("length", bytes.length)
                  .add("hash", Arrays.hashCode(bytes));
        } else {
            helper.addValue(bytes);
        }
        return helper.toString();
    }
@Test
    public void testToString() {
        final byte[] some = new byte[] {2, 5, 0, 1 };
        final String expected = "byte[]{length=" + some.length + ", hash=" + Arrays.hashCode(some) + "}";

        assertEquals(expected, String.valueOf(ByteArraySizeHashPrinter.of(some)));
        assertNotNull(ByteArraySizeHashPrinter.orNull(some));
    }