environment property Null safety
The environment for this process as a map from string key to string value.
The map is unmodifiable, and its content is retrieved from the operating system on its first use.
Environment variables on Windows are case-insensitive, so on Windows the map is case-insensitive and will convert all keys to upper case. On other platforms, keys can be distinguished by case.
static Map<String, String> get environment => _Platform.environment;