code: protected ObjectId readObjectId() throws IOException {
  		int time = ByteOrderUtil.flip(_in.readInt());
  		int machine = ByteOrderUtil.flip(_in.readInt());
  		int inc = ByteOrderUtil.flip(_in.readInt());
  		return new ObjectId(time, machine, inc);
  	}
docs: Reads a ObjectID from the input stream
  @return the ObjectID
  @throws IOException if the ObjectID could not be read