The following properties are taken into consideration when items is set and the corresponding buttons are created.
Changes made to properties marked (observed) will be reflected in the corresponding buttons.
title (observed)image (observed)enabled (observed)widthtargetactiontitleTextAttributesForState:TODO(featherless): File bugs to observe the rest of the properties.
Note: in order to make Button Bar reflect changes to not-observed properties you must clear the MDCButtonBar instance's items property and reset it, like so:
actionItem.target = <some other target> let items = buttonBar.items buttonBar.items = nil buttonBar.items = items
actionItem.target = <some other target>; NSArray *items = buttonBar.items; buttonBar.items = nil; buttonBar.items = items;