fixedFooter property
The fixed footer shown at the bottom of this card.
Setting fixedFooter without specifying a primaryButton or a
secondaryButton causes an error. For Chat apps, you can use fixed
footers in
dialogs, but not
card messages.
[Google Workspace add-ons and Chat
apps](https://developers.google.com/workspace/extend):
Implementation
GoogleAppsCardV1CardFixedFooter? fixedFooter;