RemoteRawObject
    content  PersistJSONValue
    received UTCTime

OutboxItem
    person    PersonId
    activity  PersistJSONValue
    published UTCTime

RemoteDiscussion
    actor         RemoteSharerId Maybe
    instance      InstanceId
    ident         Text
    discuss       DiscussionId
    unlinkedActor Text           Maybe

    UniqueRemoteDiscussionIdent instance ident
    UniqueRemoteDiscussion discuss

LocalMessage
    author         PersonId
    rest           MessageId
    unlinkedParent Text      Maybe

    UniqueLocalMessage rest

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

    UniqueRemoteMessageIdent instance ident
    UniqueRemoteMessage rest