The code for delta_extrema is slow in the perf checks

[Azzaare]

I have no idea yet if it makes sense algorithmically, but the checks are quite slow. Might be worth it to investigate.

[Azzaare]

After profiling, the following code does run-time dispatch.

function δ_extrema(X...)
    M = map(extrema ∘ Iterators.flatten, X) # culprit
    _minmax(t1, t2) = min(t1[1], t2[1]), max(t1[2], t2[2])
    m = reduce(_minmax, M; init = (Inf, -Inf))
    return m[2] - m[1]
end

The reason being that the eltype of each collection in X are unknown.