Gtk.TreeViewColumn.prototype.set_resizable

function set_resizable(resizable:Boolean):void {
    // Gjs wrapper for gtk_tree_view_column_set_resizable()
}

If resizable is true, then the user can explicitly resize the column by grabbing the outer edge of the column button. If resizable is true and sizing mode of the column is #GTK_TREE_VIEW_COLUMN_AUTOSIZE, then the sizing mode is changed to #GTK_TREE_VIEW_COLUMN_GROW_ONLY.