Gets the add-in for this chat room. An add-in is a web page that can be embedded in a chat room. The chat room interacts with the add-in, sending it notification of inbound and outbound messages. The add-in also has access to metadata about the chat room and the messages which are posted to it. An add-in must be registered with the system before it can be used on a chat room.
Assembly: Microsoft.Rtc.Collaboration.PersistentChat (in Microsoft.Rtc.Collaboration.PersistentChat.dll)
Property valueType: Microsoft.Rtc.Collaboration.PersistentChat.PersistentChatAddIn