chore: checkpoint before Python removal

vendor/hashbrown/benches/insert_unique_unchecked.rs

@@ -0,0 +1,34 @@
+//! Compare `insert` and `insert_unique_unchecked` operations performance.
+
+#![feature(test)]
+
+extern crate test;
+
+use hashbrown::HashMap;
+use test::Bencher;
+
+#[bench]
+fn insert(b: &mut Bencher) {
+    let keys: Vec<String> = (0..1000).map(|i| format!("xxxx{}yyyy", i)).collect();
+    b.iter(|| {
+        let mut m = HashMap::with_capacity(1000);
+        for k in &keys {
+            m.insert(k, k);
+        }
+        m
+    });
+}
+
+#[bench]
+fn insert_unique_unchecked(b: &mut Bencher) {
+    let keys: Vec<String> = (0..1000).map(|i| format!("xxxx{}yyyy", i)).collect();
+    b.iter(|| {
+        let mut m = HashMap::with_capacity(1000);
+        for k in &keys {
+            unsafe {
+                m.insert_unique_unchecked(k, k);
+            }
+        }
+        m
+    });
+}