Proof using.
unfold message_enables_label.
intros.
find_apply_lem_hyp in_split.
break_exists_name xs. break_exists_name ys.
unfold enabled.
destruct (ServerNetHandler n Unlock (nwState net Server)) eqn:?.
destruct p. destruct p.
cut (l0 = MsgUnlock); intros.
subst.
- repeat eexists. econstructor; eauto.
- handler_unfold. repeat break_match; repeat find_inversion; auto.
Qed.

Lemma Unlock_delivered_MsgUnlock :
forall n,
message_delivered_label (mkPacket n Server Unlock) MsgUnlock.