setJson method
Sets a JSON flag.
value must be JSON-encodable: null, a number, string, or bool, or lists
and string-keyed maps of those. Throws an ArgumentError otherwise, and a
StateError after shutdown
Implementation
void setJson(String key, Object? value) {
final String encoded;
try {
encoded = jsonEncode(value);
} catch (_) {
throw ArgumentError.value(value, 'value', 'must be JSON encodable');
}
_backend.set(key, StoredJson(encoded));
}