Currently VectorClock/VectorClockMutable provide pure virtual methods that are implemented in concrete classes by calling back into VectorClock/VectorClockMutable methods for the necessary Components. (eg. gossipOut calls one of gossipOutInternal or gossipOutExternal, which is implemented in the concrete classes by calling _gossipOutComponent). This provides a lot of flexibility that isn't really needed, at the cost of a confusing call chain and overly excessive use of protected methods.

Better would be for the pure virtual methods to return an indication of which Components should be gossiped/ticked/persisted, with the base class then doing the appropriate operations on those Components. This will allow _gossipOutComponent et al to be private, rather than protected. The obvious choices for how the concrete classes should indicate which Components are relevant are std::vector<Component> or ComponentArray<bool>.