Ltac set_up_net_handlers :=
    intros;
    match goal with
      | [ H : context [ NetHandler (pDst ?p) _ _ _ ] |- _ ] =>
        destruct (pDst p) eqn:?
    end; simpl in *;
    [find_apply_lem_hyp ClientNetHandler_cases |
     find_apply_lem_hyp ServerNetHandler_cases; intuition; try break_exists ];
    intuition; subst;
    simpl in *; intuition;
    repeat find_rewrite;
    repeat find_inversion;
    simpl in *;
    try now rewrite update_nop_ext.

Lemma locks_correct_unlock_at_head : forall sigma p c, pSrc p = Client c -> pBody p = Unlock -> locks_correct_unlock sigma p -> at_head_of_queue sigma c.