@Override
  protected void prepareBuffer() {
    super.prepareBuffer();
    bufferToSend.writeShort(VERSION_V1);
    bufferToSend.writeByte(isCaughtUp ? (byte) 1 : 0);
  }
@return {@code true} if replicas have caught up. {@code false} otherwise.
ambry-protocol/src/main/java/com/github/ambry/protocol/CatchupStatusAdminResponse.java