Google Pub/Sub as a transport

[zeagord]

Support google pub/sub as a transport similar to kafka, aws-kinesis.

Referencing original request - #45

[codefromthecrypt]

@zeagord Nov 23 21:59

We are actually moving some of our services to GCP. And our span storage is in the on-premise. So it would be nice for us to use pub/sub and collect it on-premise. And the data transport cost it very less as well.

[elefeint]

@zeagord is this feature still useful for you?

[zeagord]

@elefeint - Unfortunately no. I was hoping to do it part of my previous job, I have to check with them. I remember doing it outside this repo purely to reduce the support effort for us at zipkin (https://github.com/ascendcorp/zipkin-forwarder/tree/gcp-pub-sub)

[codefromthecrypt]

This needs to be attached to the module (auto-configuration) for the server to use it. Help wanted!