static inline
    void silc_buffer_purge(SilcBuffer sb);

    Same as silc_buffer_free but free's only the contents of the buffer
    not the buffer itself.  The `sb' remains intact, data is freed.  Buffer
    is ready for re-use after calling this function.

    Must not be called for buffers allocated with silc_buffer_salloc,
    silc_buffer_salloc_size, silc_buffer_scopy and silc_buffer_sclone.