@VisibleForTesting
    State state() {
        final State state = this.state.get();
        assert state != null;
        return state;
    }
Creates a new {@link NonBlockingCircuitBreaker} with the specified {@link Ticker} and
{@link CircuitBreakerConfig}.
core/src/main/java/com/linecorp/armeria/client/circuitbreaker/NonBlockingCircuitBreaker.java