ListPicker
A list picker displays a list of items, and information about the items, such as product name, description, and image, in the Messages app on the customer's device. The customer can interact multiple times with one or more items from the list. Each interaction should send a reply (on behalf of the user) together with the postback value.
Properties
Attachments provided with the message. This field can be empty. It contains attachments that the user or agent sent alongside with the message.
Author associated with this message.
The direction in which the message is sent.
Optional fallback text which can be used if UI integration doesn't support concrete subtype of Message.
The otherwise uncategorizable properties for this message. It can contain anything from message status to custom properties.