SilcBool silc_packet_send_va(SilcPacketStream stream,
                                 SilcPacketType type,
                                 SilcPacketFlags flags, ...);

    Same as silc_packet_send but takes the data in as variable argument
    formatted buffer (see silcbuffmt.h).  The arguments must be ended
    with SILC_STR_END.  Returns FALSE if packet could not be sent or
    the buffer could not be formatted.

    // Send NEW_CLIENT packet
    silc_packet_send_va(stream, SILC_PACKET_NEW_CLIENT, 0,
                        SILC_STR_UI_SHORT(username_len),
                        SILC_STR_DATA(username, username_len),
                        SILC_STR_UI_SHORT(realname_len),
                        SILC_STR_DATA(realname, realname_len),
                        SILC_STR_END);