Macro binrw_enum 

macro_rules! binrw_enum {
    (
        #[repr($ty:ty)]
        $(#[$meta:meta])*
        $vis:vis enum $name:ident {
            $($variant:ident = $value:expr),* $(,)?
        }
    ) => { ... };
}

Macro to implement BinRead + BinWrite for repr(xx) enums