Function validate_actors 

pub fn validate_actors<'a, A, S, I>(
    init_contexts: I,
    _store: Pin<&'a impl Datastore>,
) -> I
where
    A: ActorList<'a, InitContexts = I>,
    S: IntoSlots,

Internal helper that for given sets of actors and slots validates the guarantees around slot access that we want to always uphold.

init_contexts is a cons-list of the init-context values for the actors in A. It is required to be passed here to drive type-inference for A but then just returned.

_store is the reference to the store the actors will use. A copy is passed in here as the lifetime of this reference may be required for the init-contexts inference.