string static method
Creates a persistent string state container.
Implementation
static PersistroMastro<String> string(
  String key, {
  String initial = '',
  bool autoSave = true,
}) {
  return PersistroMastro<String>(
    key: key,
    initial: initial,
    decoder: (json) => json,
    encoder: (value) => value,
    autoSave: autoSave,
  );
}