putPresignedPart method
A part of a presigned session, PUT to the object store URL of the session (12 3.3);
returns the ETag. Throws like putPart.
Implementation
String putPresignedPart(String fileId, int number, Uint8List bytes) {
final f = files[fileId];
if (f == null) throw const FakeProblem(404, 'not_found');
return _storePart(f, number, null, bytes)['etag']! as String;
}