cbb_buffer_add
if (!CBB_flush(cbb) || !cbb_buffer_add(cbb->base, &buf, len_len))
if (!cbb_buffer_add(cbb->base, NULL, extra_bytes))
if (!cbb_buffer_add(cbb->base, &prefix_bytes, len_len))
if (!CBB_flush(cbb) || !cbb_buffer_add(cbb->base, &dest, len))
if (!CBB_flush(cbb) || !cbb_buffer_add(cbb->base, out_data, len))
if (!CBB_flush(cbb) || !cbb_buffer_add(cbb->base, &buf, len_len))
if (!cbb_buffer_add(cbb->base, NULL, extra_bytes))
if (!cbb_buffer_add(cbb->base, &prefix_bytes, len_len))
if (!CBB_flush(cbb) || !cbb_buffer_add(cbb->base, &dest, len))
if (!CBB_flush(cbb) || !cbb_buffer_add(cbb->base, out_data, len))