Macro cookie_factory::gen_be_u64

macro_rules! gen_be_u64 {
    ($i:expr, $val:expr) => { ... };
}

gen_be_u64!(I, u8) => I -> Result<I,E> Write an unsigned 8 bytes integer (using big-endian order).

 let r = gen_be_u64!((&mut mem,0),0x0102030405060708u64);