feat: put len before xs

src/array_string.rs

@@ -31,10 +31,11 @@ use serde::{Serialize, Deserialize, Serializer, Deserializer};
 /// The string is a contiguous value that you can store directly on the stack
 /// if needed.
 #[derive(Copy)]
+#[repr(C)]
 pub struct ArrayString<const CAP: usize> {
     // the `len` first elements of the array are initialized
-    xs: [MaybeUninit<u8>; CAP],
     len: LenUint,
+    xs: [MaybeUninit<u8>; CAP],
 }
 
 impl<const CAP: usize> Default for ArrayString<CAP>