mapUrl constant Null safety
Implementation
static const String mapUrl =
'https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=es_CL&gl=US';
static const String mapUrl =
'https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=es_CL&gl=US';