ManualGenComposition.swift

Gen(unGen: { r, n in
    let splitGen: () -> StdGen = {
        var g: StdGen = r.split.0
        return {
            g = g.split.0
            return g
        }
    }()
    
    let Foo = Foo()
    foo.a = Bool.arbitrary.unGen(splitGen(),n)
    foo.b = Int8.arbitrary.unGen(splitGen(),n)
    foo.c = Float.arbitrary.unGen(splitGen(),n)
})