code: @SuppressWarnings("unchecked")
      protected void readFromSerializedStream(final ObjectInputStream stream) throws IOException, ClassNotFoundException {
          cas = stream.readLong();
          expiry = stream.readInt();
          id = stream.readUTF();
          content = (T) stream.readObject();
          mutationToken = (MutationToken) stream.readObject();
      }
docs: Helper method to create the document from an object input stream, used for serialization purposes.
  
  @param stream the stream to read from.
  @throws IOException
  @throws ClassNotFoundException