Is there a Julia binding to the GtkFixed container?

I’m trying to position a Gtk Button with width=50, and height=40 at location 10,300 in a GtkLayout container.
This is what I have tried:

using Gtk
win = GtkWindow("Button Example", 400, 300)
layout = GtkLayout(400, 300)
btn = GtkButton("Click Me")
put!(layout, btn, 10, 300)
push!(win, layout)

This code does not work.
Am I trying to do something that is not possible with the current state of Gtk.jl at this time?