@Override
  protected void prepareBuffer() {
    super.prepareBuffer();
    bufferToSend.writeBytes(blobId.toBytes());
    bufferToSend.writeLong(expiresAtMs);
    bufferToSend.writeLong(operationTimeInMs);
  }
@param correlationId the correlation id for the request
@param clientId the id of the client generating the request
@param blobId the blob ID whose TTL needs to be updated
@param expiresAtMs the absolute time (in ms) at which the blob must expire
@param operationTimeMs the time of the operation (in ms)
@param version the version of the TtlUpdateRequest
ambry-protocol/src/main/java/com/github/ambry/protocol/TtlUpdateRequest.java