[Help] Serializer/Deserializer for type using variable length encoding scheme

For example, I hava a strcut defined as follow:
```rust
pub struct VariableLength(u32);
```

And the field using a variable length encoding scheme, how can I implement Serializer/Deserializer for it?

```text
VaribaleLength <---> Vec<u8>/&[u8]
```

Thanks a lot.