Init enter game

KcpSharp/Base/KcpSendReceiveQueueItemCache.cs

@@ -0,0 +1,76 @@
+#if NEED_LINKEDLIST_SHIM
+using LinkedListOfQueueItem = KcpSharp.NetstandardShim.LinkedList<(KcpSharp.KcpBuffer Data, byte Fragment)>;
+using LinkedListNodeOfQueueItem = KcpSharp.NetstandardShim.LinkedListNode<(KcpSharp.KcpBuffer Data, byte Fragment)>;
+#else
+using LinkedListNodeOfQueueItem =
+    System.Collections.Generic.LinkedListNode<(KianaBH.KcpSharp.Base.KcpBuffer Data, byte Fragment
+        )>;
+using LinkedListOfQueueItem =
+    System.Collections.Generic.LinkedList<(KianaBH.KcpSharp.Base.KcpBuffer Data, byte Fragment)>;
+#endif
+
+namespace KianaBH.KcpSharp.Base;
+
+internal sealed class KcpSendReceiveQueueItemCache
+{
+    private readonly LinkedListOfQueueItem _list = new();
+    private SpinLock _lock;
+
+    public LinkedListNodeOfQueueItem Rent(in KcpBuffer buffer, byte fragment)
+    {
+        var lockTaken = false;
+        try
+        {
+            _lock.Enter(ref lockTaken);
+
+            var node = _list.First;
+            if (node is null)
+            {
+                node = new LinkedListNodeOfQueueItem((buffer, fragment));
+            }
+            else
+            {
+                node.ValueRef = (buffer, fragment);
+                _list.RemoveFirst();
+            }
+
+            return node;
+        }
+        finally
+        {
+            if (lockTaken) _lock.Exit();
+        }
+    }
+
+    public void Return(LinkedListNodeOfQueueItem node)
+    {
+        node.ValueRef = default;
+
+        var lockTaken = false;
+        try
+        {
+            _lock.Enter(ref lockTaken);
+
+            _list.AddLast(node);
+        }
+        finally
+        {
+            if (lockTaken) _lock.Exit();
+        }
+    }
+
+    public void Clear()
+    {
+        var lockTaken = false;
+        try
+        {
+            _lock.Enter(ref lockTaken);
+
+            _list.Clear();
+        }
+        finally
+        {
+            if (lockTaken) _lock.Exit();
+        }
+    }
+}