void connectTo(ActivityRegistry &)
the argument's signals are propagated to the Service's held by the token
void copySlotsFrom(ActivityRegistry &)
the copy the argument's slots to the token's signals
void copySlotsTo(ActivityRegistry &)
copy our Service's slots to the argument's signals
void connect(ActivityRegistry &)
the argument's signals will forward the token's signals
std::shared_ptr< edm::serviceregistry::ServicesManager > manager_