pushPreferredWidth
Causes the minimum and/or natural width to grow if the new proposed sizes exceed the current minimum and natural width.
This is used by GtkCellAreaContext
implementations during the request process over a series of GtkTreeModel
rows to progressively push the requested width over a series of gtk_cell_area_get_preferred_width() requests.
Parameters
minimumWidth
the proposed new minimum width for @context
naturalWidth
the proposed new natural width for @context