PolicyEvent:
| RetryAttemptEvent
| RetryExhaustedEvent
| TimeoutTriggeredEvent
| CircuitOpenEvent
| CircuitHalfOpenEvent
| CircuitClosedEvent
| CacheHitEvent
| CacheMissEvent
| CacheRejectedEvent
| CacheInvalidatedEvent
| FallbackUsedEvent
| SemaphoreQueuedEvent
| SemaphoreAcquiredEvent
| SemaphoreReleasedEvent
| OverlapStartedEvent
| OverlapQueuedEvent
| OverlapDroppedEvent
| OverlapCompletedEvent
| KeyedLockQueuedEvent
| KeyedLockAcquiredEvent
| KeyedLockReleasedEvent