@VisibleForTesting
  @Nullable
  Integer getUploadBufferSizeBytes() {
    return uploadBufferSizeBytes;
  }
@Test
  public void testUploadBufferSizeUserSpecified() {
    GcsOptions pipelineOptions = gcsOptionsWithTestCredential();
    pipelineOptions.setGcsUploadBufferSizeBytes(12345);
    GcsUtil util = pipelineOptions.getGcsUtil();
    assertEquals((Integer) 12345, util.getUploadBufferSizeBytes());
  }