DataOutputStream dout = new DataOutputStream(out);
    dout.writeByte(SignedBytes.checkedCast(strategy.ordinal()));
    dout.writeByte(UnsignedBytes.checkedCast(numHashFunctions)); // note: checked at the c'tor
    dout.writeInt(bits.data.length());
    for (int i = 0; i < bits.data.length(); i++) {
      dout.writeLong(bits.data.get(i));
    }
  }

  /**