private static ClientRequestContext newContext() {
        return ClientRequestContext.builder(HttpRequest.of(HttpMethod.GET, "/"))
                                   .eventLoop(eventLoop.get())
                                   .build();
    }
Tests the case where a delegate raises an exception rather than returning a response.
core/src/test/java/com/linecorp/armeria/client/limit/ConcurrencyLimitingClientTest.java