Hello, and thanks for all the great examples!
I've gotten the COAP transport for background DFU working on my custom hardware platform and app, however I have noticed that occasionally the DFU process will hang, with the app never retrying a block request. If I add a periodic `coap_dfu_reset_state`, and `coap_dfu_trigger`, the dfu process will continue. How can I access the current progress of the DFU procedure so that I can set a timeout in the application? I see that there is a way to get a diagnostic struct with `coap_dfu_diagnostic_get`, but the fields of interest about total/current block progress seem to only be updated during a multicast update.
Additionally, I have found some bugs that I needed to fix to get the example working without compiler warnings with gcc. In particular, the assert on line 486 in `nrf_dfu_req_handler.c` had to be commented out, as the background dfu does not actually set the `callback.write` function pointer.
In `background_dfu_block.c` there were warnings about comparison between unsigned and signed integers on lines 156, 394, and 440, and should be explicitly cast.
In `nrf_log_backend_interface.h` the use of STRINGIFY on line 148 should be explicitly cast to a `char *` to avoid a warning about disregarding a const.
