GtkCellRendererSpinner renders a spinning animation in a cell, very similar to Spinner.
It can often be used as an alternative to a CellRendererProgress for
displaying indefinite activity, instead of actual progress.
To start the animation in a cell, set the active property to
true and increment the pulse property
at regular intervals. The usual way to set the cell renderer properties for each cell is to bind them to columns in your tree model using
e.g. gtk_tree_view_column_add_attribute.