chore: checkpoint before Python removal

vendor/pin-project/examples/unsafe_unpin.rs

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// See ./unsafe_unpin-expanded.rs for generated code.
+
+#![allow(dead_code, clippy::undocumented_unsafe_blocks)]
+
+use pin_project::{UnsafeUnpin, pin_project};
+
+#[pin_project(UnsafeUnpin)]
+struct Struct<T, U> {
+    #[pin]
+    pinned: T,
+    unpinned: U,
+}
+
+unsafe impl<T: Unpin, U> UnsafeUnpin for Struct<T, U> {}
+
+fn main() {}