default void onEventCountUpdated(String circuitBreakerName,
                                     com.linecorp.armeria.common.util.EventCount eventCount) throws Exception {}
Invoked when the circuit breaker's internal {@link com.linecorp.armeria.common.util.EventCount} is
updated.
core/src/main/java/com/linecorp/armeria/client/circuitbreaker/CircuitBreakerListener.java