class GrpcOutputStream extends OutputStream {

  @Override
  public void close() throws IOException {
    flushBuffer(true);
    LOG.info("Sent {} bytes for container {}",
        writtenBytes, containerId);
    responseObserver.onCompleted();
    buffer.close();
  }

    GrpcOutputStream(
      StreamObserver<CopyContainerResponseProto> responseObserver,
      long containerId, int bufferSize);

}