chore: checkpoint before Python removal

vendor/try-lock/README.md

@@ -0,0 +1,44 @@
+# TryLock
+
+- [Crates.io](https://crates.io/crates/try-lock)
+- [Docs](https://docs.rs/try-lock)
+
+A light-weight lock guarded by an atomic boolean.
+
+Most efficient when contention is low, acquiring the lock is a single atomic swap, and releasing it just 1 more atomic swap.
+
+## Example
+
+```rust
+use std::sync::Arc;
+use try_lock::TryLock;
+
+// a thing we want to share
+struct Widget {
+    name: String,
+}
+
+// lock it up!
+let widget1 = Arc::new(TryLock::new(Widget {
+    name: "Spanner".into(),
+}));
+
+let widget2 = widget1.clone();
+
+
+// mutate the widget
+let mut locked = widget1.try_lock().expect("example isn't locked yet");
+locked.name.push_str(" Bundle");
+
+// hands off, buddy
+let not_locked = widget2.try_lock();
+assert!(not_locked.is_none(), "widget1 has the lock");
+
+// ok, you can have it
+drop(locked);
+
+let locked2 = widget2.try_lock().expect("widget1 lock is released");
+
+assert_eq!(locked2.name, "Spanner Bundle");
+```
+