See gioui.org.
./TestWindows/testwindows.go is an application that tests the new window options. You can maximize, minimize, fullscreen, center, size, position windows either from the command line or by clicking on buttons.
Example:
>go run testwindows.go -test=n
where n is one of the following:
1 = Maximized window
2 = Minimized window
3 = Centered window
4 = Positioned window
5 = Sized window
6 = Fullscreen window
Dual MIT/Unlicense; same as Gio