Add comments to connection_check_event().

    (conn->read_event && event_pending(conn->read_event, EV_READ, NULL));

}

/** Check whether <b>conn</b> is correct in having (or not having) a

 * read/write event (passed in <b>ev</b). On success, return 0. On failure,

 * log a warning and return -1. */

static int

connection_check_event(connection_t *conn, struct event *ev)

{

  int bad;

  if (conn->type == CONN_TYPE_AP && TO_EDGE_CONN(conn)->is_dns_request) {

    /* DNS requests which we launch through the dnsserv.c module do not have

     * any underlying socket or any underlying linked connection, so they

     * shouldn't have any attached events either.

     */

    bad = ev != NULL;

  } else {

    /* Everytyhing else should have an underlying socket, or a linked

     * connection (which is also tracked with a read_event/write_event pair).

     */

    bad = ev == NULL;

  }