With this function, the window can be docked to the edge of the screen, similar to the Windows taskbar.

This feature is only available under Windows.

This way you can test whether the platform supports docking:
final dockable = await windowManager.isDockable();

To dock the window you can call this function
await windowManager.dock(side: DockSide.LEFT, width: 100);

To undock the window you can call this function
await windowManager.undock();