void write_altsvc(DefaultMemchunks *buf, BlockAllocator &balloc,
                  const AltSvc &altsvc) {
  buf->append(util::percent_encode_token(balloc, altsvc.protocol_id));
  buf->append("=\"");
  buf->append(util::quote_string(balloc, altsvc.host));
  buf->append(':');
  buf->append(altsvc.service);
  buf->append('"');
}
void write_altsvc(DefaultMemchunks *buf, BlockAllocator &balloc,
                  const AltSvc &altsvc) {
  buf->append(util::percent_encode_token(balloc, altsvc.protocol_id));
  buf->append("=\"");
  buf->append(util::quote_string(balloc, altsvc.host));
  buf->append(':');
  buf->append(altsvc.service);
  buf->append('"');
}