add lifetime comment

Author: Marc Pabst

wgpu-hal/src/dx12/mod.rs

@@ -462,9 +462,9 @@ pub struct Instance {
     supports_allow_tearing: bool,
     _lib_dxgi: DxgiLib,
     flags: wgt::InstanceFlags,
-    options: wgt::Dx12BackendOptions,
     memory_budget_thresholds: wgt::MemoryBudgetThresholds,
     compiler_container: Arc<shader_compilation::CompilerContainer>,
+    options: wgt::Dx12BackendOptions,
 }
 
 impl Instance {
@@ -537,6 +537,15 @@ struct SwapChain {
     present_mode: wgt::PresentMode,
     format: wgt::TextureFormat,
     size: wgt::Extent3d,
+    options: wgt::Dx12BackendOptions,
+}
+
+impl SwapChain {
+    /// Returns the waitable handle associated with this swap chain, if any.
+    /// Handle is only valid while the swap chain is alive.
+    pub unsafe fn waitable_handle(&self) -> Option<Foundation::HANDLE> {
+        self.waitable
+    }
 }
 
 enum SurfaceTarget {
@@ -1415,6 +1424,7 @@ impl crate::Surface for Surface {
             present_mode: config.present_mode,
             format: config.format,
             size: config.extent,
+            options: device.options.clone(),
         });
 
         Ok(())