File descriptor in a signal message containing destination is closed

[kyotsumoto-sun-denshi]

If a D-Bus server sends a signal message containing destination and file descriptor,
OBus closes the file descriptor in the message.

https://github.com/ocaml-community/obus/blob/master/src/protocol/oBus_connection.ml#L459

match apply_filters "incoming" message active.incoming_filters with
   | None -> ...
   | Some message ->
       (* The internal dispatcher accepts only messages destined to
          the current connection: *)
       if active.name = "" || OBus_message.destination message = active.name then ignore (
         (try%lwt
           dispatch_message active message
         with exn ->
           Lwt_log.error ~section ~exn "message dispatching failed with")
         [%lwt.finally
           OBus_value.V.sequence_close (OBus_message.body message)]
       );

If a signal message doesn't contain destination, " OBus_value.V.sequence_close" is not called.
But If a signal message contains destination, " OBus_value.V.sequence_close" is called, file descriptor is closed.