Alex, thanks again! I see your point.
Next I would like to ask about the considerations on a protocol over interrupt IN and OUT endpoints.
I have understood host polls an IN endpoint periodically and has an internal ring buffer where it stores fetched HID reports. Hence, there is HidD_SetNumInputBuffers on Windows, for instance. Nevertheless, there is no guarantee no report(s) will be lost.
Have you thought about that? Any solution?