private String getExecutionEventsString() {
        List<HystrixEventType> executionEvents = getExecutionEvents();
        if (executionEvents == null) {
            executionEvents = Collections.emptyList();
        }
        StringBuilder message = new StringBuilder("[");
        for (HystrixEventType executionEvent : executionEvents) {
            message.append(HystrixEventType.class.getSimpleName()).append("#").append(executionEvent.name())
                .append(",");
        }
        for (SofaAsyncHystrixEvent event : events) {
            message.append(SofaAsyncHystrixEvent.class.getSimpleName()).append("#").append(event.name()).append(",");
        }
        if (message.length() > 1) {
            message.deleteCharAt(message.length() - 1);
        }
        return message.append("]").toString();
    }
{@link HystrixCommand} for async requests

@author <a href=mailto:scienjus@gmail.com>ScienJus</a>
fault/fault-hystrix/src/main/java/com/alipay/sofa/rpc/hystrix/SofaAsyncHystrixCommand.java