Github user cshannon commented on the issue:
https://github.com/apache/activemq-artemis/pull/1853
@clebertsuconic - No, I'm not trying to measure the size on the JVM. I
want to measure the size of the messages in general (including how much space
is on disk) as a metric to know how much data is left to consume on the Queue.
The most accurate way is to use the encode size as this is the amount of space
taken up on disk. For large messages this also includes the body size.---
