The usecase is to establish communication between Salesforce and Downstream system using PubSub API, I tried going through / for the same. Lets say I've Change Data Capture event on Opportunity. When some change is there then Python Client will subscribe it to read it , now if vice versa to perform how can I read it in Salesforce.As it says the services are in .proto file but not able to understand how can we use it in Salesforce side or is there any way around.