Callback to clean up after filtering has been applied
Specified as filter.cleanup, this is an optional callback invoked
after the filter has been applied. If the check or apply callbacks
allocated a payload to keep per-source filter state, use this
callback to free that payload and release resources as required.
Callback to clean up after filtering has been applied
Specified as filter.cleanup, this is an optional callback invoked after the filter has been applied. If the check or apply callbacks allocated a payload to keep per-source filter state, use this callback to free that payload and release resources as required.