fix: LateInitializationError when specifying initialCameraFit

lib/src/gestures/flutter_map_interactive_viewer.dart

@@ -17,14 +17,16 @@ import 'package:flutter_map/src/map/options/options.dart';
 import 'package:flutter_map/src/misc/point_extensions.dart';
 import 'package:latlong2/latlong.dart';
 
+typedef InteractiveViewerBuilder = Widget Function(
+  BuildContext context,
+  MapOptions options,
+  MapCamera camera,
+);
+
 /// Applies interactions (gestures/scroll/taps etc) to the current [MapCamera]
 /// via the internal [controller].
 class FlutterMapInteractiveViewer extends StatefulWidget {
-  final Widget Function(
-    BuildContext context,
-    MapOptions options,
-    MapCamera camera,
-  ) builder;
+  final InteractiveViewerBuilder builder;
   final FlutterMapInternalController controller;
 
   const FlutterMapInteractiveViewer({

lib/src/map/options/options.dart

@@ -99,7 +99,7 @@ class MapOptions {
   /// and you need to access the controller as soon as the map is built.
   /// Otherwise you can use WidgetsBinding.instance.addPostFrameCallback
   /// In initState to controll the map before the next frame.
-  final void Function()? onMapReady;
+  final VoidCallback? onMapReady;
 
   final LatLngBounds? maxBounds;
 

lib/src/map/widget.dart

@@ -142,7 +142,6 @@ class _FlutterMapStateContainer extends State<FlutterMap>
     return LayoutBuilder(
       builder: (context, constraints) {
         _updateAndEmitSizeIfConstraintsChanged(constraints);
-        _applyInitialCameraFit(constraints);
 
         return FlutterMapInteractiveViewer(
           controller: _flutterMapInternalController,
@@ -235,6 +234,8 @@ class _FlutterMapStateContainer extends State<FlutterMap>
             oldCamera,
             newMapCamera,
           );
+
+          _applyInitialCameraFit(constraints);
         }
       });
     }