@Override
    public boolean isCircuitBreakerException(Exception ex) {
        return ex instanceof UnprocessedRequestException &&
               ex.getCause() instanceof CallNotPermittedException;
    }
Creates a default {@link CircuitBreakerClientHandler} which uses the provided
{@link CircuitBreakerMapping} to handle requests.
resilience4j2/src/main/java/com/linecorp/armeria/resilience4j/circuitbreaker/client/Resilience4JCircuitBreakerClientHandler.java