StructArrays + custom broadcasting + Makie

General Usage
5

I see now, thanks again. This helped convince me:

julia> struct Foo{Ta,Tb,Tc}
                a::Ta
                b::Tb
                c::Tc
              end

julia> f(T::Type{<:Foo}) = println("hello from f1")
f (generic function with 1 method)

julia> f(T::Type{Foo{Ta,Tb,Tc}}) where {Ta,Tb,Tc} = println("hello from f2")
f (generic function with 2 methods)

julia> foo = Foo(1,2,3)
Foo{Int64, Int64, Int64}(1, 2, 3)

julia> f(typeof(foo))
hello from f2

julia> f(Union{})
hello from f1

julia>