usize should be Into<u64> iff usize is <= 64 bit. usize is already on that hook: `0x100000000usize` will fail to compile in 32 bit, so you already risk compile

usize should be Into<u64> iff usize is <= 64 bit. usize is already on that hook: `0x100000000usize` will fail to compile in 32 bit, so you already risk compile errors when switching archs. As it is I'm just writing `as u64` which is clearly worse.