feat(perf): perform bbox culling prior to aggressive culling for polylines

lib/src/layer/polygon_layer/polygon.dart

@@ -115,7 +115,7 @@ class Polygon<R extends Object> {
 
   LatLngBounds? _boundingBox;
 
-  /// Get the bounding box of the [Polygon.points] (cached).
+  /// Get the bounding box of the [points] (cached).
   LatLngBounds get boundingBox =>
       _boundingBox ??= LatLngBounds.fromPoints(points);
 

lib/src/layer/polyline_layer/polyline.dart

@@ -42,6 +42,12 @@ class Polyline<R extends Object> {
   /// {@macro fm.hde.hitValue}
   final R? hitValue;
 
+  LatLngBounds? _boundingBox;
+
+  /// Get the bounding box of the [points] (cached).
+  LatLngBounds get boundingBox =>
+      _boundingBox ??= LatLngBounds.fromPoints(points);
+
   /// Create a new [Polyline] used for the [PolylineLayer].
   Polyline({
     required this.points,

lib/src/layer/polyline_layer/polyline_layer.dart

@@ -145,6 +145,10 @@ class _PolylineLayerState<R extends Object> extends State<PolylineLayer<R>>
     for (final projectedPolyline in polylines) {
       final polyline = projectedPolyline.polyline;
 
+      // Test bounding boxes to avoid potentially expensive aggressive culling
+      // when none of the line is visible
+      if (!boundsAdjusted.isOverlapping(polyline.boundingBox)) continue;
+
       // Gradient poylines cannot be easily segmented
       if (polyline.gradientColors != null) {
         yield projectedPolyline;