`GtkGestureSingle` is a `GtkGestures` subclass optimized for singe-touch and mouse gestures.
Under interaction, these gestures stick to the first interacting sequence, which is accessible through [
method@Gtk.GestureSingle.get_current_sequence] while the gesture is being interacted with.
By default gestures react to both gdk_button_primary and touch events. [
method@Gtk.GestureSingle.set_touch_only] can be used to change the touch behavior. Callers may also specify a different mouse button number to
interact with through [method@Gtk.GestureSingle.set_button], or react to any mouse button by setting it to 0. While the gesture is active, the
button being currently pressed can be known through [method@Gtk.GestureSingle.get_current_button].