* changes to it will <i>not</i> be reflected in this {@code HashCode} object or any other arrays
   * returned by this method.
   */
  // TODO(user): consider ByteString here, when that is available
  public abstract byte[] asBytes();

  /**
   * Copies bytes from this hash code into {@code dest}.
   *
   * @param dest the byte array into which the hash code will be written

   * changes to it will <i>not</i> be reflected in this {@code HashCode} object or any other arrays
   * returned by this method.
   */
  // TODO(user): consider ByteString here, when that is available
  public abstract byte[] asBytes();

  /**
   * Copies bytes from this hash code into {@code dest}.
   *
   * @param dest the byte array into which the hash code will be written

the core type of <code>T</code> is called <code>bytestring</code>.
</p>

<p>
Examples of interfaces with <code>bytestring</code> core types:
</p>

<pre>
interface{ int }                          // int (same as ordinary core type)
interface{ []byte | string }              // bytestring
interface{ ~[]byte | myString }           // bytestring
</pre>

<p>

  // 2. the order is deterministic and easy to understand, for debugging purpose.
  @SuppressWarnings("ComparableType")
  private static final class ByToString implements Comparable<Object>, Serializable {
    private static final ByToString INSTANCE = new ByToString();

    @Override
    public int compareTo(Object o) {
      return toString().compareTo(o.toString());
    }

    @Override

  // 2. the order is deterministic and easy to understand, for debugging purpose.
  @SuppressWarnings("ComparableType")
  private static final class ByToString implements Comparable<Object>, Serializable {
    private static final ByToString INSTANCE = new ByToString();

    @Override
    public int compareTo(Object o) {
      return toString().compareTo(o.toString());
    }

    @Override