Messaging: design transaction instrumentation

[lmolkova]

#163 (comment)

Many messaging systems support transactional publish and settlement, but the spec does not provide any guidance on how to instrument them

[lmolkova]

For example, in Azure Service Bus transactions do not directly affect operation flow. User initiates a transaction, then performs each operation as usual, but with additional transaction context, and then, when the transaction is committed, broker performs all the operations.

I.e. for the Azure ServiceBus, we'd be looking for one extra attribute to represent transaction Id.

More investigation is needed for popular messaging systems to see if any general solution could/should be implemented.