chore: checkpoint before Python removal

vendor/pin-utils/tests/stack_pin.rs

@@ -0,0 +1,21 @@
+#![forbid(unsafe_code)] // pin_mut! is completely safe.
+
+use pin_utils::pin_mut;
+use core::pin::Pin;
+
+#[test]
+fn stack_pin() {
+    struct Foo {}
+    let foo = Foo {};
+    pin_mut!(foo);
+    let _: Pin<&mut Foo> = foo;
+
+    let bar = Foo {};
+    let baz = Foo {};
+    pin_mut!(
+        bar,
+        baz,
+    );
+    let _: Pin<&mut Foo> = bar;
+    let _: Pin<&mut Foo> = baz;
+}