Improve rate limiting logic in Pub/Sub Receiver
The current logic for rate limiting in the Pub/Sub receiver only evaluates rate windows on a once-per-second basis. This can cause the receiver to "skip" some of the message windows when the system is under heavy load, thus decreasing overall throughput.
Using the existing token-bucket logic, increase the bucket window from 1 second to 10 seconds. This allows the receiver to handle small load spikes and allows the receiver to fetch larger message batches as needed.