try {
        output.writeShort(v);
      } catch (IOException impossible) {
        throw new AssertionError(impossible);
      }
    }

    @Override
    public void writeUTF(String s) {
      try {
        output.writeUTF(s);
      } catch (IOException impossible) {
        throw new AssertionError(impossible);
      }
    }

    @Override
    public byte[] toByteArray() {