[xer0x]

There is a "post-invocation phase" for tidying up. It's not long, and it's enough for things like Datadog's metrics plugin to send off some numbers. Yet it will fail, if you have too many metrics. It's fuzzy.

[Scaevolus]

You only get that when you register extensions: https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtime-...