globalPersist method
Returns a RxPersistBool, with the persistent key of key.
Default value to this if the persistent storage returns null.
Usage: defaultBoolValue.globalPersist(key)
ex.
final persistVar = false.globalPersist(key);
Implementation
RxPersistBool globalPersist(String key) {
return RxPersistBool(key, this);
}