chore: checkpoint before Python removal

vendor/zerocopy/benches/formats/coco_dynamic_padding.rs

@@ -0,0 +1,24 @@
+use zerocopy_derive::*;
+
+// The only valid value of this type are the bytes `0xC0C0`.
+#[derive(TryFromBytes, KnownLayout, Immutable)]
+#[repr(u16)]
+pub enum C0C0 {
+    _XC0C0 = 0xC0C0,
+}
+
+#[derive(FromBytes, KnownLayout, Immutable, SplitAt)]
+#[repr(C, align(4))]
+pub struct Packet<Magic> {
+    magic_number: Magic,
+    milk: u8,
+    mug_size: u8,
+    temperature: [u8; 5],
+    marshmallows: [[u8; 3]],
+}
+
+/// A packet begining with the magic number `0xC0C0`.
+pub type CocoPacket = Packet<C0C0>;
+
+/// A packet beginning with any two initialized bytes.
+pub type LocoPacket = Packet<[u8; 2]>;