No, there is not. The multi_receive_encoded method in the filter receives a batch of events. It processes them all and then calls the rotate_if_needed function. It deliberately only calls fstat once for the entire batch as an optimisation.
That works @Badger but, as you suggested, performance is really bad as there could be tons of these events. I actually question the validity of this requirement and will go back to the users and try to change it. Thanks so much for giving me the solution!