Someimes we have code that generates random values, but we don't really care about the randomness. Maybe we just need to know the shape of the result, or we're doing smoke testing. In these cases, the result of random sampling would be fine, but we might like to have something simpler without unnecessary overhead.
For example,
julia> using Random, ConstantRNGs
julia> randn(ConstantRNG())
0.0
julia> rand(ConstantRNG())
0.5
julia> randexp(ConstantRNG())
1.0As always, there's a relevant XKCD:
