Subscriptions retry indefinitely when MaxAttempts is not configured

[sonathaj]

I tried this:

Overview:

We've encountered an issue where the broker retries failed event deliveries indefinitely when no maxAttempts value is set in the default retry policy. This resulted in a production incident where a single failed event retried infinitely.

Environment:

• Component: CloudStreams Broker
• Affected Resource: Subscription event delivery

This happened:

1. Broker's default retry policy has null maxAttempts
2. Downstream subscriber returned HTTP 500 errors
3. Broker retried the same event continuously without limit

I expected this:

We noticed there's a DefaultMaxAttempts = 5 constant defined in RetryPolicy.cs that appears unused. We wanted to check if the current infinite retry behavior is intentional, or if the framework should apply this default when maxAttempts is not set.

Thank you for your assistance with this issue.