permanentId property
final
The permanent file identifier (typically a 16-byte MD5 hash), or null
if the document has no file identifier array.
The permanent ID is set when the document is first created and does not
change across save operations. Callers that need a hex string can use
permanentId?.map((b) => b.toRadixString(16).padLeft(2, '0')).join().
Implementation
final Uint8List? permanentId;