typedef void (*SilcSFTPStatusCallback)(SilcSFTP sftp,
                                           SilcSFTPStatus status,
                                           const char *message,
                                           const char *language_tag,
                                           void *context);

    Status callback is called every time server returns a status packet
    for a request the client has made. The `status' indicates the type
    of the status.  The `message' is optional error message received from
    the server, in language indicated by the `language_tag'.  Both of
    these pointers may be NULL.