@AfterEach
    public void cleanUp() {
        HystrixTestHelper.reset();
    }
Integration test for hystrix-core 1.5.3+ traces the following :
<p>
<tt>HystrixObservableCommand.observe()</tt>
<tt>HystrixObservableCommand.toObservable()</tt>
<p>
Additionally, the cause of fallback should be traced via AbstractCommand.getFallbackOrThrowException() invocation.

@author Jiaqi Feng
@author HyunGil Jeong
agent-module/plugins-it/hystrix-it/src/test/java/com/navercorp/pinpoint/it/plugin/hystrix/HystrixObservableCommand_1_5_3_to_1_5_x_IT.java