Updating Label value twice in the same Makie event handler

Specific Domains Visualization
1

in the MWE below, “start” is never displayed. is there a way to make it so?

using GLMakie
f = Figure()
b = Button(f[1,1], label="foo")
l = Label(f[1,2], "")
on(b.clicks) do _
    l.text[] = "start"
    sleep(1)   # long running calculation
    l.text[] = "finish"
end
2

The problem is sleep is running in the same task as the GUI updates, so until this function returns no graphical updates can happen. The solution is to launch the long-running function in its own task:

using GLMakie
f = Figure()
b = Button(f[1,1], label="foo")
l = Label(f[1,2], "")
on(b.clicks) do _
    l.text[] = "start"
    @async begin
        sleep(1)   # long running calculation
        l.text[] = "finish"
    end
end