Additional information in the message
Summary list of the combined messages, recommended to use the content of the first three messages
Name list: for one-to-one chats it contains both parties' names; for group chats it contains the group name
Number of combined messages
Combined message content. Only has a value when the JSON-serialized content is less than 120K; otherwise stored remotely as a file.
File name when the JSON-serialized content exceeds 120K. Mobile clients use this field to determine whether a file needs to be downloaded.
Remote file URL, only present when jsonMsgKey has a value
Combined (forwarded) message bundle;
channelTypereplaces engineconversationType.