I want to explore if it's possible to improve the performance of the Google Pub/Sub component.
I did some experimenting with replacing the com.google.apis:google-api-services-pubsub library with com.google.cloud:google-cloud-pubsub and replacing the synchronous pull with the asynchronous one. I've also created a cache for the message producers.
This combination lead to a significant improvement. More than 50 times faster in a simple test with a producer in a splitter with parallel processing and a consumer with concurrent consumers.
I'd like to invite the community to see if these changes are in right direction and help out to take it further.