Removes a filter.
Note that since filters run in a different thread, there is a race condition where it is possible that the filter will be running even after calling remove_filter, so you cannot just free data that the filter might be using. Instead, you should pass a DestroyNotify to add_filter, which will be called when it is guaranteed that the data is no longer needed.
| this | |
| filter_id |
an identifier obtained from add_filter |