issues with kill_kaleido and restart

[disberd]

There seem to be some weird behavior with killing and restarting the process.

For what concerns killing, at least in the master code, killing kaleido does not seem to actually stop the underlying process as savefig can still be called and execute succesfully.

Try the following code:

using PlotlyKaleido
using PlotlyBase

begin
	PlotlyKaleido.start()
	PlotlyKaleido.kill_kaleido()
	@info "Immediately" PlotlyKaleido.is_running()
	sleep(0.1)
	@info "After sleep" PlotlyKaleido.is_running()
	savefig(Plot(rand(4)), "test.png") # This should not work but it correctly saves the figure
end

which outputs

┌ Info: Immediately
└   PlotlyKaleido.is_running() = true
┌ Info: After sleep
└   PlotlyKaleido.is_running() = false
"test.png"

and correctly generate the png file.

The issue with is_running() only returning false after a small amount of time after a call to kill_kaleido() is what also cause issues with restart() as the command has to be called twice to actually restart the process, as the call here:

PlotlyKaleido.jl/src/PlotlyKaleido.jl

Lines 24 to 28 in d0c390c

	restart() = (kill_kaleido(); start())
	function start()
	is_running() && return

will simply exit from start() called immediately after kill_kaleido() because the process is seen as running still.