call method
Gets a provider for the given parameter.
Implementation
Provider<T> call(P parameter) {
  return _providers.putIfAbsent(
    parameter,
    () => Provider<T>(() => _creator(parameter), singleton: _singleton),
  );
}
Gets a provider for the given parameter.
Provider<T> call(P parameter) {
  return _providers.putIfAbsent(
    parameter,
    () => Provider<T>(() => _creator(parameter), singleton: _singleton),
  );
}