[Question] Application Insights internal telemetry client settings and NodeJS runtime

Azure functions v2 NodeJS runtime

#### Question

Hi @brettsam, I read [here](https://github.com/Azure/azure-functions-host/issues/5235#issuecomment-553615017) that with C# runtime you can get the internal AI client.

I've read the docs abot the NodeJS runtime, but I cannot find an answer to some questions related to AI client instantiation:

1) ~~`applicationInsights.defaultClient` is a singleton across all functions that belong to the same functionapp service ?~~
2) ~~if it is a singleton, when I call `setup()` in one functions, I'm overriding the configuration of all clients for every other function ?~~
3) how does `applicationInsights.defaultClient` relate to the internal ai client used by the function runtime ? when I call `setup()` on this client, does it affect the internal client as well ?
4) if not, is there a way to get / configure the internal AI client in JS functions ?

I'm mostly asking because we're experiencing SNAT port exhaustion and we want to try passing a custom http agent to the AI client (but there are other use cases as well).

Thank you in advance for any answer !

(I've answered 1 & 2 myself and it looks like the answer is _yes_ to both)