Receive CloudEvent and URL query parameters

CloudEvent signature type function is really useful.

I'm working on build a flow as below.
```
Pub/Sub topic A -> Eventarc A -v
Pub/Sub topic B -> Eventarc B ---> Function
Pub/Sub topic C -> Eventarc C -^
```
I would like to receive CloudEvents from several topics in the same Function instance and adjust the processing somewhat for each topic.

Eventarc allows to specify a service URL path when invoking a destination Function. So, I adjust the behavior of Function to fit the Pub/Sub Topic by using URL query parameters like `/?mailTo=foo@example.com`, `/?mailTo=bar@example.com` and so on.
This service URL path can be easily edited from the Cloud Console for ease of operation.

The current CloudEvent signature Function does not seem to have a way to obtain URL query parameters.
So I use the http signature type Function and unmarshall the Pub/Sub message and control the http response myself.

If we can use URL query parameters in CloudEvent signature type, we can build a more convenient and flexible system.
Is there a way to recieve URL query parameters in CloudEvent signature Function?
Or is there another better way?

Thanks.

El issue no menciona archivos ni pruebas. Empieza rastreando el manejo de solicitudes de firma de CloudEvent en functions-framework-nodejs y determina si los parámetros de consulta de la URL están expuestos; se considera completado cuando exista una forma documentada y probada de acceder a ellos o una alternativa confirmada por un maintainer.

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