Background: Thanks to help of this community I've been able to create quite nice hobby app interfacing external devices - my friend have many models I can't test personally and it happens that those behave "slightly" different that I expected reading specs To diagnose problems I need debug file created on user devices (here is the prblem) and sent to me (this part is simple).
The problem: is log must be created sequentially as data comes-in asynchronously (from USB or BT serial) - so I can not first make a big list and write it to file at the end or later (similar to: Can't write file to SHARED directories on API31 (Android 12) - #15 by TIMAI2 but I can't apply previous solution).
Any suggestions ?