SessionConversationScope plus the conversation's owner, for a conversation addressed without a session.
The conversation's ExternalID (the anonymous scope id), or null when it has none or was not read.
ExternalID
Whether the caller could read the conversation (false when the session has none).
Conversation.UserID, or null when the conversation was not read.
Conversation.UserID
SessionConversationScope plus the conversation's owner, for a conversation addressed without a session.