Optional
cancellableWhen included on a partial_item, indicates if the stream can be cancelled. If so, a "stop streaming" button will display in the UI.
An identifier for this item within the full message response. This ID is used to correlate a partial or complete item chunk with other chunks that represent the same item. This ID is only unique for a given message response.
Optional
stream_Indicates if the stream has stopped which will trigger the UI to respond with appropriate a11y states and messaging.
Additional metadata associated with a specific message item (response type) inside of a message response.