From Distributions.jl source:
https://github.com/JuliaStats/Distributions.jl/blob/9b7a3483ae5e96a77d406cdce8aa9de0180484f0/src/common.jl#L12
Can’t a discrete distribution have a support over real numbers outside of integers? In that case,
Base.eltype(::Type{Discrete}) = Int
seems wrong