Added virtual destructor to class IUnknownImpl
diff --git a/src/D3D12MemAlloc.h b/src/D3D12MemAlloc.h
index 33500d6..6d9fbd0 100644
--- a/src/D3D12MemAlloc.h
+++ b/src/D3D12MemAlloc.h
@@ -123,6 +123,7 @@
 class IUnknownImpl : public IUnknown

 {

 public:

+    virtual ~IUnknownImpl() = default;

     virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void** ppvObject);

     virtual ULONG STDMETHODCALLTYPE AddRef();

     virtual ULONG STDMETHODCALLTYPE Release();