This plugin will only work on events ingested after the plugin was enabled. This means it will register events as being the first if there were events that occured before it was enabled. To mitigate this, you could consider renaming the relevant events and creating an action that matches both the old event name and the new one.
This plugin will set all configured properties to null inside an ingested event. Usually it makes sense to place this plugin at the end of the plugin chain.
Note when specifying $ip, additionally event.ip will be removed.
Heavily inspired by https://github.com/PostHog/first-time-event-tracker