Macro ordermap::dispatch_32_vs_64

macro_rules! dispatch_32_vs_64 {
    ($self_:ident . $method:ident::<$($t:ty),*>($($arg:expr),*)) => { ... };
    ($self_:ident . $method:ident ($($arg:expr),*)) => { ... };
}

Call self.method(args) with ::<u32> or ::<u64> depending on self size class.

The u32 or u64 is prepended to the type parameter list!