chore: checkpoint before Python removal

vendor/spin/examples/debug.rs

@@ -0,0 +1,21 @@
+extern crate spin;
+
+fn main() {
+    let mutex = spin::Mutex::new(42);
+    println!("{:?}", mutex);
+    {
+        let x = mutex.lock();
+        println!("{:?}, {:?}", mutex, *x);
+    }
+
+    let rwlock = spin::RwLock::new(42);
+    println!("{:?}", rwlock);
+    {
+        let x = rwlock.read();
+        println!("{:?}, {:?}", rwlock, *x);
+    }
+    {
+        let x = rwlock.write();
+        println!("{:?}, {:?}", rwlock, *x);
+    }
+}