Modulo bias in prefix generation

[jasper-d]

The modulo operation in

nuid/nuid.go

Line 132 in 57049d7

n.pre[i] = digits[int(cbs[i])%base]

causes a bias towards the first 8 digits (0-7). These digits occur with a probability of 5/256 while the rest of the digits occur with a probability of 4/256.

Using a base that is a power of 2 would guarantee a uniform distribution. It would also open up the possibility to exploit power of 2 for mod and div operations.