Resolver for `Forwarded` header see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Forwarded
function forwardedResolver(ctx) {
  const header = ctx.request.header['forwarded'];

  if (!header) {
    return false;
  } else {
    const forwarded = parseForwarded(header);
    return forwarded.proto === 'https';
  }
}