@Override
  public String toString() {
    return "FileMetadata{" +
        "creationTimeMillis=" + creationTimeMillis +
        ", lastModifiedTimeMillis=" + lastModifiedTimeMillis +
        ", size=" + size +
        ", owner='" + owner + '\'' +
        ", group='" + group + '\'' +
        ", permissions=" + permissions +
        '}';
  }
Representation of metadata associated with a File.
samza-core/src/main/java/org/apache/samza/storage/blobstore/index/FileMetadata.java