What is the general way to know structures of a class (instance) provided by 3rd party?

I am new to Flutter (Dart) and this may be a basic question.

I got my current geolocation with geolocator API like the following:

Position position = await Geolocator().getCurrentPosition(desiredAccuracy: LocationAccuracy.high);

After getting the position, I was planning to set Lat and Long to separate variables for future use.
With a bit of struggle, I finally managed to figure out the right property to get Lat/Long information by type hint from Android Studio.

...
late double Lat;
late double Long;
...
          Lat = snapshot.data!.latitude;
          Long = snapshot.data!.longitude;
          print("Lat is "+Lat.toString());
          print("Long is "+Long.toString());

When typing 'snapshot.data!.', Android Studio shows options available. By looking at property names, I could have guessed which one of these should be the one. However, I don't believe relying on type hint is ideal way to find right property name.

For example, in Javascript, we can console.log() to get detailed information of a specific instance including accessible properties and we can tell property name with actual values at logged. I tried print() but it doesn't show a property name. (In above case, print(snapshot.data!.toString()) shows {Lat:xxx, Long:xxx}, but actual property names are 'latitude' and 'longitude').

Is there any general way to get detailed information of a specific instance including accessible properties in Dart?