[Bug]: quantile not working for ExponentialFamily.jl distributions

[abpolym]

I wanted to call quantile on some of the distributions defined by ExponentialFamily.jl.
However, I realized with horror and an immense shock that quantile does not work for any of the ExponentialFamily.jl distributions as iterate has not been defined:

julia> quantile(GammaShapeRate(1.0, 2.0), 0.001)

MethodError: no method matching iterate(::ExponentialFamily.GammaShapeRate{Float64})
Closest candidates are:
  iterate(::Automa.Precondition)
   @ Automa ~/.julia/packages/Automa/EyNRt/src/precond.jl:87
  iterate(::Automa.Precondition, ::Any)
   @ Automa ~/.julia/packages/Automa/EyNRt/src/precond.jl:87
  iterate(::Base.MethodSpecializations)
   @ Base reflection.jl:1148
  ...

The reason why I wanted to use quantile is to determine a range over which to plot a given distribution to capture all of the data, e.g.:

lo = quantile(d, 0.001)
hi = quantile(d, 0.999)
# Clip to distribution support (might not be necessary but just a safety measure)
lo_supp, hi_supp = extrema(support(d))
lo = max(lo, lo_supp)
hi = min(hi, hi_supp)
xs = range(lo, hi, length=npoints)
ys = pdf.(d, xs)

[wouterwln]

Do we know what distributions this is not implemented for? For example, for multivariate distributions, the quantile function is not defined, and for most univariate distributions in Distributions.jl it is already defined. So are we talking about only our custom Normal and Gamma parametrizations?