[Feature] Support FIFO Queues in AWS transport

[iancooper]

Is your feature request related to a problem? Please describe. Because of our Broker based model, and the lack of support for FIFO based queues via SNS, we have not supported AWS FIFO SQS queues as they were not available from SNS. They now are. https://aws.amazon.com/blogs/aws/introducing-amazon-sns-fifo-first-in-first-out-pub-sub-messaging/

Describe the solution you'd like

• We want to support declaring a channel as FIFO for AWS SNS scenarios
• We want to support the use of message groups to allow multiple performers (or consumers) to process messages in the FIFO queue by group. This should work due to the visibility of a group depending on the timeout, but any shared buffer would needs to bucket by a message group id if there is one, and then only give work to that thread, so it might be better not to use a shared buffer with a FIFO queue to allow the SQS queue to handle ensuring that only one thread processes a group at one time.

Describe alternatives you've considered The alternative is not to support FIFO queues and ask customers to use "latest wins" as a strategy instead. This is the situation today