void silc_net_gethostbyaddr_async(const char *addr,
                                      SilcSchedule schedule,
                                      SilcNetResolveCallback completion,
                                      void *context)

    Asynchronously resolves the hostname for the IP address indicated
    by the `addr'.  This function returns immediately, and the
    `completion' callback will be called after the resolving is
    completed.