Gtk.TreeView.prototype.get_dest_row_at_pos

function get_dest_row_at_pos(drag_x:Number, drag_y:Number):Boolean {
    // Gjs wrapper for gtk_tree_view_get_dest_row_at_pos()
}

Determines the destination row for a given position. drag_x and drag_y are expected to be in widget coordinates. This function is only meaningful if tree_view is realized. Therefore this function will always return false if tree_view is not realized or does not have a model.