Publisher confirms should be sent in batch

[kyrrem]

When sending multiple messages in a rebus transaction, it takes a lot of time to confirm each message individually. Since we are reusing the same IModel from the current transaction, it should be safe to confirm all messages in one go. The performance difference when running inside a rebus transaction is huge.

Batch confirms is also recommended from the RabbitMQ webside due to performance and latency.

I extended the current performance tests to also run in transaction to be able to compare side by side.

[kyrrem]

Wanted to connect this issue with the following PR rebus-org/Rebus.RabbitMq#40

But didnt find a way to do that, a bit new to github.

[kyrrem]

This should be in Rebus.RabbitMQ, not Rebus main. Closing.