_chacha20poly1305_final
_chacha20poly1305_final(&ctx, dst + len, src + len, src_len - len);
return _chacha20poly1305_final(&ctx, dst + len, src + len,
ret = _chacha20poly1305_final(ctx, block, block, len) ?
ret = _chacha20poly1305_final(ctx, block, block, len) ?