Similar to c69670c85b, allows to eliminate one
allocation and reduce memory footprint a bit (tested on tx decoding):
name old time/op new time/op delta
DecodeFromBytes-8 1.78µs ± 3% 1.79µs ± 2% ~ (p=1.000 n=10+10)
name old alloc/op new alloc/op delta
DecodeFromBytes-8 888B ± 0% 800B ± 0% -9.91% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
DecodeFromBytes-8 11.0 ± 0% 10.0 ± 0% -9.09% (p=0.000 n=10+10)