{
      size_t need = buf->misalign + buf->off + datlen;
      size_t oldoff = buf->off;

      if (buf->totallen < need) {
            if (evbuffer_expand(buf, datlen) == -1)
                  return (-1);
      }

      memcpy(buf->buffer + buf->off, data, datlen);
      buf->off += datlen;

      if (datlen && buf->cb != NULL)
            (*buf->cb)(buf, oldoff, buf->off, buf->cbarg);

      return (0);
}