Offload node score buffers

Solver/Crafty/ArenaBuffer.cs

@@ -5,7 +5,7 @@ using System.Runtime.CompilerServices;
 namespace Craftimizer.Solver.Crafty;
 
 // Adapted from https://github.com/dtao/ConcurrentList/blob/4fcf1c76e93021a41af5abb2d61a63caeba2adad/ConcurrentList/ConcurrentList.cs
-public struct ArenaBuffer<T>
+public struct ArenaBuffer<T> where T : struct
 {
     // Technically 25, but it's very unlikely to actually get to there.
     // The benchmark reaches 20 at most, but here we have a little leeway just in case.
@@ -17,39 +17,41 @@ public struct ArenaBuffer<T>
 
     private static int BatchCount = MaxSize / BatchSize;
 
-    public T[][] Data;
+    public ArenaNode<T>[][] Data;
     private int index; // Unused in single threaded workload
     private int count;
 
     public readonly int Count => count;
 
-    public void AddConcurrent(T node)
+    public void AddConcurrent(ArenaNode<T> node)
     {
         if (Data == null)
-            Interlocked.CompareExchange(ref Data, new T[BatchCount][], null);
+            Interlocked.CompareExchange(ref Data, new ArenaNode<T>[BatchCount][], null);
 
         var idx = Interlocked.Increment(ref index) - 1;
 
         var (arrayIdx, subIdx) = GetArrayIndex(idx);
 
         if (Data[arrayIdx] == null)
-            Interlocked.CompareExchange(ref Data[arrayIdx], new T[BatchSize], null);
+            Interlocked.CompareExchange(ref Data[arrayIdx], new ArenaNode<T>[BatchSize], null);
 
+        node.ChildIdx = (arrayIdx, subIdx);
         Data[arrayIdx][subIdx] = node;
 
         Interlocked.Increment(ref count);
     }
 
-    public void Add(T node)
+    public void Add(ArenaNode<T> node)
     {
-        Data ??= new T[BatchCount][];
+        Data ??= new ArenaNode<T>[BatchCount][];
 
         var idx = count++;
 
         var (arrayIdx, subIdx) = GetArrayIndex(idx);
 
-        Data[arrayIdx] ??= new T[BatchSize];
+        Data[arrayIdx] ??= new ArenaNode<T>[BatchSize];
 
+        node.ChildIdx = (arrayIdx, subIdx);
         Data[arrayIdx][subIdx] = node;
     }