Is `Vecotr{UInt8}(string)`

the fastest way to convert String to bytes? From my testing, it seems to perform ok

```
const M = 100_000_000; const K = 100
const s = rand([@sprintf "id%03d" k for k in 1:K], M)
function ghi(s::Vector{S}) where S<:AbstractString
prod.(Vector{UInt8}.(s))
end
@time ghi(s)
```

**Background**

I was looking into radixsort for strings for which there is an implementation in R. I can sort 100 million strings of varying length in 6 seconds in R. The sorting performance for strings in Julia is 38 seconds, see below

```
const M = 100_000_000; const K = 100
idstr = rand([@sprintf "id%03d" k for k in 1:K], M)
@time sort(idstr)
@time sort(idstr)
```

I think being able to sort vectors of String in a performant manner is key to unlocking data manipulation performance.

Thatâ€™s why I wanted to understand whatâ€™s the most performant way to make the underlying bytes available.