alt Hacker NewsWhat you are describing is usually part of analytics platforms (Mixpanel, etc.). A feature flag toggle only plays a small part in this (but it may also be used for a lot of other scenarios of how you may want to control feature flags).
Audience is decided by analytics tool -> Feature flag server maps audience to feature flag value -> Analytics tool tracks its events and includes feature flag value as attribute
So if you want to slowly roll out a feature flag, you need to get a different app involved that can do everything the feature flag tool can do and a whole lot more? What’s the point of the feature flag tool?
Analytics is a much broader set of tooling. It can (and should) report similar things.