Observable for holding any Univariate Distribution

General Usage
1

How would one create an Observable to hold any univariate distribution?

If I do,

using Interact, Distributions
h = Observable(Normal())

The observable only accepts Normals, so the following fails:

h[] = Gamma()
2

You can create an Observable with type Distribution, but beware of performance problems since this is not a concrete type.

julia> typeof(Normal())
Normal{Float64}

julia> supertype(ans)
Distribution{Univariate, Continuous}

julia> h = Observable{Distribution}()
Observable{Distribution}(#undef)


julia> h[] = Normal()
Normal{Float64}(μ=0.0, σ=1.0)

julia> h[] = Gamma()
Gamma{Float64}(α=1.0, θ=1.0)