RemoteRawObject
    content  PersistJSONObject
    received UTCTime

RemoteDiscussion
    sharer        RemoteSharerId
    instance      InstanceId
    ident         Text
    discuss       DiscussionId

    UniqueRemoteDiscussionIdent instance ident
    UniqueRemoteDiscussion discuss

LocalMessage
    author         PersonId
    rest           MessageId

    UniqueLocalMessage rest

RemoteMessage
    author     RemoteSharerId
    instance   InstanceId
    ident      Text
    rest       MessageId
    raw        RemoteRawObjectId
    lostParent Text              Maybe

    UniqueRemoteMessageIdent instance ident
    UniqueRemoteMessage rest