How to treat received Message batches:
- Whole Batch = don't process child Message documents individually; accumulate and send the whole batch as one composite document
- Single-Session Batch = forward each message in the batch as part of a single session, followed objects representing the batch headers / trailers
- Multi-Session Batch = forward each message in the batch in its own session, including objects representing the batch headers / trailers
- Individual = forward each child message in the batch in its own session; do not forward objects representing the batch headers / trailers