getCountryCodeForRegion method
Returns the country calling code for a specific region. For example, this would be 1 for the United States, and 64 for New Zealand.
regionCode
the region that we want to get the country calling code for.
getCountryCodeForRegion returns the country calling code for
the region denoted by regionCode.
Implementation
int getCountryCodeForRegion(String? regionCode) {
if (!_isValidRegionCode(regionCode)) return 0;
return _getCountryCodeForValidRegion(regionCode);
}