cairo/canvas.go
func (v *Context) destroy() {
	if v.context != nil {
		C.cairo_destroy(v.native())
		v.context = nil
	}
}
func (v *Context) destroy() {
	if v.context != nil {
		C.cairo_destroy(v.native())
		v.context = nil
	}
}
// destroy is a wrapper around cairo_destroy().