ash/instance: Allow building instance from handle+fns

Adds a constructor to build an instance device from a handle + functions.
Helps with interoperability with other vulkan wrappers

ash/src/instance.rs

@@ -33,6 +33,23 @@ impl Instance {
         }
     }
 
+    pub fn from_parts(
+        handle: vk::Instance,
+        instance_fn_1_0: vk::InstanceFnV1_0,
+        instance_fn_1_1: vk::InstanceFnV1_1,
+        instance_fn_1_2: vk::InstanceFnV1_2,
+        instance_fn_1_3: vk::InstanceFnV1_3,
+    ) -> Self {
+        Self {
+            handle,
+
+            instance_fn_1_0,
+            instance_fn_1_1,
+            instance_fn_1_2,
+            instance_fn_1_3,
+        }
+    }
+
     #[inline]
     pub fn handle(&self) -> vk::Instance {
         self.handle