cdc: replace Key::to_raw with Key::into_raw to reduce allocation (#7895)
cdc: replace Key::to_raw with Key::into_raw to reduce allocation (#7895)

Signed-off-by: Neil Shen <cce998fdf3749d1bb26a297634a107d1dc0875fa@gmail.com>
c4pt0r/tikv,pingcap/tikv,BusyJay/tikv,BusyJay/tikv,pingcap/tikv,BusyJay/tikv,BusyJay/tikv