fix(emqx_stomp_protocol): fix Dialyzer warnings

apps/emqx_stomp/src/emqx_stomp_protocol.erl

@@ -396,20 +396,20 @@ receipt_id(Headers) ->
 
 handle_recv_send_frame(#stomp_frame{command = <<"SEND">>, headers = Headers, body = Body}, State) ->
     Topic = header(<<"destination">>, Headers),
-    maybe_send_receipt(receipt_id(Headers), State),
-    emqx_broker:publish(
+    _ = maybe_send_receipt(receipt_id(Headers), State),
+    _ = emqx_broker:publish(
         make_mqtt_message(Topic, Headers, iolist_to_binary(Body))
     ),
     State.
 
 handle_recv_ack_frame(#stomp_frame{command = <<"ACK">>, headers = Headers}, State) ->
     Id = header(<<"id">>, Headers),
-    maybe_send_receipt(receipt_id(Headers), State),
+    _ = maybe_send_receipt(receipt_id(Headers), State),
     ack(Id, State).
 
 handle_recv_nack_frame(#stomp_frame{command = <<"NACK">>, headers = Headers}, State) ->
     Id = header(<<"id">>, Headers),
-     maybe_send_receipt(receipt_id(Headers), State),
+     _ = maybe_send_receipt(receipt_id(Headers), State),
      nack(Id, State).
 
 ensure_clean_trans_timer(State = #pstate{transaction = Trans}) ->
@@ -468,4 +468,4 @@ interval(incoming_timer, #pstate{heart_beats = HrtBt}) ->
 interval(outgoing_timer, #pstate{heart_beats = HrtBt}) ->
     emqx_stomp_heartbeat:interval(outgoing, HrtBt);
 interval(clean_trans_timer, _) ->
-    ?TRANS_TIMEOUT.
+    ?TRANS_TIMEOUT.