Function all_ids 

pub fn all_ids<S, A, Store, Props, R, Sch>(
    model: &StandardModel<S, A, Store, Props, R, Sch>,
) -> Vec<AgentId> 
where
    A: Agent,
    S: Space,
    Store: AgentStore<A>,
    R: RngCore,
    Sch: Scheduler<StandardModel<S, A, Store, Props, R, Sch>>,

Get a vector of all agent IDs in the model.