Currently:

````
julia> r = 10^8:-1:1;

julia> @time extrema(r)
elapsed time: 2.915793305 seconds (96 bytes allocated)
(1,100000000)

julia> @time (minimum(r), maximum(r))
elapsed time: 7.621e-6 seconds (96 bytes allocated)
(1,100000000)
````
`extrema` needs to be specialized for ranges. Shall add that and use here.