Major Description
PIP-70 https://github.com/apache/pulsar/wiki/PIP-70%3A-Introduce-lightweight-raw-Message-metadata Introduced a broker level entry metadata and already support add message index and broker add a timestamp for the message.
But currently, the client can't get the broker level message metadata since the broker skip this information when dispatching messages to the client. Provide a way to expose the broker level message metadata to the client.