chore: checkpoint before Python removal

vendor/pin-project/examples/enum-default.rs

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// See ./enum-default-expanded.rs for generated code.
+
+#![allow(dead_code)]
+
+use pin_project::pin_project;
+
+#[pin_project(project = EnumProj)]
+enum Enum<T, U> {
+    Pinned(#[pin] T),
+    Unpinned(U),
+}
+
+fn main() {}