We are currently having an issue where our masking transforms are not working due to the length of _raw being too large. If we set LOOKAHEAD to a higher value the masking works. _raw has request.body at the end of the event. Since request.body is the only relevant part of the event from a transform perspective, we tried to set as the SOURCE_KEY, but it doesn't seem to do anything and there's no logs from what we can see.   Tried SOURCE_KEY = request.body or SOURCE_KEY = request   and tried with   [acceptable_keys] request = request.body   or    [acceptable_keys] request = request     How do we use SOURCE_KEY to limit where the transforms regex is applying?   ... View more