Is it possible to remove empty attributes when they are created through a regex parser? I am pulling in my firewall logs through a udplog receiver. I am running a regex_parser on that receiver to extract and tag information from the log (like src_ip, protocol, etc.). That regex is capturing a lot of optional groups that are not present in all logs. For example, if it's an https connection the log will list a tls_version, but if it's an http connection that field isn't there. But it seems all capture groups are being added to all of the logs as attributes, though most of them are empty. Is there a way to not add those empty attributes?