perf(fill): avoid redundant bounds recomputation

OpenNest.Core/Part.cs

@@ -206,6 +206,7 @@ namespace OpenNest
         /// </summary>
         public void UpdateBounds()
         {
+            PerfCounters.CountPartBoundsUpdate();
             BoundingBox = Program.BoundingBox();
             BoundingBox.Offset(Location);
         }

OpenNest.Core/PerfCounters.cs

@@ -14,12 +14,14 @@ namespace OpenNest
         private static long partIntersects;
         private static long fillScoreComputations;
         private static long partBoundaryPreparations;
+        private static long partBoundsUpdates;
 
         public static long FindBestFits => Interlocked.Read(ref findBestFits);
         public static long OffsetPerimeterEntities => Interlocked.Read(ref offsetPerimeterEntities);
         public static long PartIntersects => Interlocked.Read(ref partIntersects);
         public static long FillScoreComputations => Interlocked.Read(ref fillScoreComputations);
         public static long PartBoundaryPreparations => Interlocked.Read(ref partBoundaryPreparations);
+        public static long PartBoundsUpdates => Interlocked.Read(ref partBoundsUpdates);
 
         [Conditional("DEBUG")]
         public static void CountFindBestFits() => Interlocked.Increment(ref findBestFits);
@@ -37,6 +39,9 @@ namespace OpenNest
         [Conditional("DEBUG")]
         public static void CountPartBoundaryPreparation() => Interlocked.Increment(ref partBoundaryPreparations);
 
+        [Conditional("DEBUG")]
+        public static void CountPartBoundsUpdate() => Interlocked.Increment(ref partBoundsUpdates);
+
         public static void Reset()
         {
             Interlocked.Exchange(ref findBestFits, 0);
@@ -44,6 +49,7 @@ namespace OpenNest
             Interlocked.Exchange(ref partIntersects, 0);
             Interlocked.Exchange(ref fillScoreComputations, 0);
             Interlocked.Exchange(ref partBoundaryPreparations, 0);
+            Interlocked.Exchange(ref partBoundsUpdates, 0);
         }
     }
 }