Update tutorial to support Lambda Provisioned Concurrency

[boxabirds]

Provisioned Concurrency, announced Dec 2019, takes some steps towards alleviating the cold start problem.

This means polling hacks can be removed.

The proposal therefore is to update the guide to at the least mention provisioned concurrency, and/or as part of it, demonstrate how to use it, and how it improves latency.

[jayair]

Yeah I think it's worth showing how to use it.

But I'm curious about the polling hacks. I don't think we do that in the guide?

[boxabirds]

Hi @jayair -- not in the coding parts of the guide, no, but there are various mentions throughout the doc on cold starts. So maybe the first increment would be to add a note in the narrative section initially, and then maybe later a more advanced element.

[jayair]

I see. Thanks for the feedback!