Function xts_mode::get_tweak_default

pub fn get_tweak_default(sector_index: u128) -> [u8; 16]

This is the default way to get the tweak, which just consists of separating the sector_index in an array of 16 bytes with little endian. May be called to get the tweak for every sector or passed directly to (en/de)crypt_area, which will basically do that.