checkUrlExists method
Returns true
if the uri
exists,
false
if getting the page encountered problems.
A cached UrlChecker implementation should override this method,
wrap it in a cached callback, still invoking it via super.checkUrlExists()
.
Implementation
Future<bool> checkUrlExists(Uri uri) async {
return await safeUrlCheck(uri,
userAgent: 'pana/$packageVersion (https://pub.dev/packages/pana)');
}