Clarify layer merge order

[pranavmarla]

Describe the bug The current documentation contains contradictory information regarding which lambda layer (auto-instrumentation vs collector) should be merged/added to the lambda first.

Specifically:

1. The auto-instrumentation doc says you should add the collector layer first:

See the Collector Lambda layer guidance to add the layer to your application and configure the Collector. We recommend you add this first.

2. The collector doc implies you should add the auto-instrumentation layer first:

Once you’ve instrumented your application you should add the Collector Lambda layer to collect and submit your data to your chosen backend.

What did you expect to see?

• If the order in which the layers are merged into your lambda matters, clearly state what the recommended order is -- i.e. which layer we should add first: Auto-instrumentation or Collector?
• If the order does NOT matter, then clearly state that instead.

[github-actions[bot]]

This issue was marked stale. It will be closed in 30 days without additional activity.

[tylerbenson]

@rapphil does the layer order matter? I don't think it does.

[serkan-ozal]

@tylerbenson @rapphil I had some layer ordering issues in Thundra, so according to my experience, as long as layers have different paths under /opt, it is not a problem because there is no conflict/overlap. Otherwise, as far as I remember, last layer will be exported later and its content will override previous ones in case of conflict.

So, as far as I see, there is no possible conflict between collector layer and any instrumentation layer, layer order should not matter.