module ActiveStorage::Blob::Identifiable

def download_identifiable_chunk
  service.download_chunk key, 0...4.kilobytes
end

def identified?
  identified
end

def identify
  update! content_type: identify_content_type, identified: true unless identified?
end

def identify_content_type
  Marcel::MimeType.for download_identifiable_chunk, name: filename.to_s, declared_type: content_type
end