ConstReadonlyLastSequence: "Nats-Last-Sequence"ReadonlySequence: "Nats-Sequence"The sequence of the republished message
ReadonlySize: "Nats-Msg-Size"The size in bytes of the message's body - Only if Republish#headers_only is set.
ReadonlyStream: "Nats-Stream"The source stream of the message
ReadonlySubject: "Nats-Subject"The original subject of the message
The stream sequence id of the last message ingested to the same original subject (or 0 if none or deleted)