Given a `Vector`

of `Pair`

s, what’s an idiomatic way of getting a vector of first and second elements in each `Pair`

? MWE:

```
x = [Pair(x,2*x) for x in 1:5]
```

then

```
julia> collect.(collect(zip(((a,b) for (a,b) in x)...))) # works, but convoluted
2-element Array{Array{Int64,1},1}:
[1,2,3,4,5]
[2,4,6,8,10]
```