Proof using.
unfold raft_net_invariant_client_request, nextIndex_safety.
simpl.
intros.
repeat find_higher_order_rewrite.
update_destruct_simplify.
- eauto using nextIndex_safety_preserved, handleClientRequest_nextIndex_preserved.
- auto.
Qed.

(* Specifications: *)
Lemma handleTimeout_nextIndex_preserved :
forall h d out d' l,
handleTimeout h d = (out, d', l) ->
nextIndex_preserved d d'.