chore: checkpoint before Python removal

vendor/zerocopy/benches/split_via_immutable_dynamic_padding.rs

@@ -0,0 +1,11 @@
+use zerocopy::*;
+
+#[path = "formats/coco_dynamic_padding.rs"]
+mod format;
+
+#[unsafe(no_mangle)]
+fn bench_split_via_immutable_dynamic_padding(
+    split: Split<&format::CocoPacket>,
+) -> (&format::CocoPacket, &[[u8; 3]]) {
+    split.via_immutable()
+}