cool size asserts because perf lmao

src/util.rs

@@ -0,0 +1,9 @@
+/// Statically asserts that the size of the type is x bytes big (on 64-bit)
+macro_rules! assert_size {
+    ($name:ident == $size:expr) => {
+        #[cfg(target_pointer_width = "64")]
+        const _: [(); $size] = [(); ::std::mem::size_of::<$name>()];
+    };
+}
+
+pub(crate) use assert_size;