-1 of -1 value in NSprogress upon deferred attachment download

Hello :slight_smile: . I have a question.
why is it i get a value of -1 of -1 when using couchbase lite method downloadAttachment: ?

I think it means that the progress is indeterminate, i.e. that no bytes have been downloaded yet. Does it change to a meaningful progress value after a moment?

It doesnโ€™t, seems like progress it not updated. Have you used downloadAttachment: before ?
by the way here is my code : https://goo.gl/Fspqev
did i miss some setting in my CBLReplicator object?