Revert "Revert the Metal Experiment (#701)"

This reverts commit fe1617ffea.

src/Ryujinx.Graphics.Metal/DisposableBuffer.cs

@@ -0,0 +1,26 @@
+using SharpMetal.Metal;
+using System;
+using System.Runtime.Versioning;
+
+namespace Ryujinx.Graphics.Metal
+{
+    [SupportedOSPlatform("macos")]
+    readonly struct DisposableBuffer : IDisposable
+    {
+        public MTLBuffer Value { get; }
+
+        public DisposableBuffer(MTLBuffer buffer)
+        {
+            Value = buffer;
+        }
+
+        public void Dispose()
+        {
+            if (Value != IntPtr.Zero)
+            {
+                Value.SetPurgeableState(MTLPurgeableState.Empty);
+                Value.Dispose();
+            }
+        }
+    }
+}