The sizing method the column uses to determine its width. Please note that %GTK_TREE_VIEW_COLUMN_AUTOSIZE are inefficient for large views, and can make columns appear choppy.
Columns only get bigger in reaction to changes in the model
Columns resize to be the optimal size every time the model changes.
Columns are a fixed numbers of pixels wide.
.g_type : UInt64
Returns the type id (GType) registered in GLib type system.