Make sure the callback function is called only once #632
Can you elaborate on why this is problematic in your case? I'm assuming your callback is doing something other than the typical "progress bar/percentage/etc" type output, but offhand I'm not sure why having the callback called 2x in a row with the same
Seems like an innocent enough change but it also feels like one of those spots where somebody else may be relying on this only-sort-of-buggy behavior, somehow.
Consider this log,
In my trivial case, the logger is called twice. In case, if some other function is called it could result in errorneous behavior.