On 1/25/21, 11:46 AM, "Marc-André Hermanns" <[email protected]> wrote: For me (although not explicitly defined in the text) that would imply that the dropped callback is only invoked once the library is in a state where a callback (and user_data) for the same level is defined and could be invoked. Does this make sense and clarify your concerns? Do you think this need more clarification in the text? I see. Yes, that makes sense for my implementation issue. Ken