getNormalizedVariant abstract method
Returns normalized variant (uppercase), or null if not specified.
This method ensures the variant is in uppercase format for consistency, though variants can contain various characters including hyphens.
Example:
final locale1 = Locale('en', 'US', 'posix');
print(locale1.getNormalizedVariant()); // Output: "POSIX"
final locale2 = Locale('en', 'US');
print(locale2.getNormalizedVariant()); // Output: null
Implementation
String? getNormalizedVariant();