checksums: speedup add-checksum-bytes by using the slice.
checksums: speedup add-checksum-bytes by using the slice.

slavapestov/factor,tgunr/factor,tgunr/factor,mrjbq7/factor,bpollack/factor,mrjbq7/factor,AlexIljin/factor,AlexIljin/factor,bjourne/factor,bjourne/factor,bjourne/factor,mrjbq7/factor,tgunr/factor,slavapestov/factor,slavapestov/factor,factor/factor,AlexIljin/factor,nicolas-p/factor,tgunr/factor,bjourne/factor,nicolas-p/factor,bpollack/factor,AlexIljin/factor,nicolas-p/factor,factor/factor,bjourne/factor,slavapestov/factor,factor/factor,nicolas-p/factor,nicolas-p/factor,bpollack/factor,factor/factor,mrjbq7/factor,bjourne/factor,slavapestov/factor,AlexIljin/factor,tgunr/factor,mrjbq7/factor,nicolas-p/factor,mrjbq7/factor,bpollack/factor,slavapestov/factor,tgunr/factor,bpollack/factor,bjourne/factor,bpollack/factor,AlexIljin/factor,nicolas-p/factor,factor/factor,AlexIljin/factor,factor/factor,bpollack/factor,slavapestov/factor