ReadonlycapacityLargest run of retries allowed when nothing has been earned yet, and the ceiling the earnings are capped at. The budget starts full, so a quiet client can still retry.
ReadonlyratioRetries allowed per call, as a share: 0.2 lets the client retry a fifth
of what it sends. Every call earns this much, spent one token per retry.
Configuration for a RetryBudget.