Function reducer

pub fn reducer<State, Action>(
    state_context: Substate<'_, Action, State, SnarkBlockVerifyState>,
    action: ActionWithMeta<&SnarkBlockVerifyAction>,
)
where
    State: SubstateAccess<SnarkBlockVerifyState> + SubstateAccess<SnarkState>,
    Action: From<SnarkBlockVerifyAction> + From<SnarkBlockVerifyEffectfulAction> + From<AnyAction> + EnablingCondition<State>,