@Override
  public BlobHttpContent getContent() {
    // TODO: Consider giving progress on manifest push as well?
    return new BlobHttpContent(
        Blobs.from(manifestTemplate), manifestTemplate.getManifestMediaType());
  }
Makes the warning for when the registry responds with an image digest that is not the expected
digest of the image.

@param expectedDigest the expected image digest
@param receivedDigests the received image digests
@return the warning message
jib-core/src/main/java/com/google/cloud/tools/jib/registry/ManifestPusher.java