gtk/tree_view_column.go
func (v *TreeViewColumn) SetSpacing(spacing int) {
	C.gtk_tree_view_column_set_spacing(v.native(), C.gint(spacing))
}
func (v *TreeViewColumn) SetSpacing(spacing int) {
	C.gtk_tree_view_column_set_spacing(v.native(), C.gint(spacing))
}
// SetSpacing() is a wrapper around gtk_tree_view_column_set_spacing().