注册插件的方式

HystrixPlugins.getInstance().registerConcurrencyStrategy(new MyHystrixConcurrencyStrategy());

public HystrixConcurrencyStrategy getConcurrencyStrategy() {
        if (concurrencyStrategy.get() == null) {
            // check for an implementation from Archaius first
            // 1
            Object impl = getPluginImplementation(HystrixConcurrencyStrategy.class);
            if (impl == null) {
                // nothing set via Archaius so initialize with default
                concurrencyStrategy.compareAndSet(null, HystrixConcurrencyStrategyDefault.getInstance());
                // we don't return from here but call get() again in case of thread-race so the winner will always get returned
            } else {
                // we received an implementation from Archaius so use it
                concurrencyStrategy.compareAndSet(null, (HystrixConcurrencyStrategy) impl);
            }
        }
        return concurrencyStrategy.get();
    }

    private <T> T getPluginImplementation(Class<T> pluginClass) {
        // 1
        T p = getPluginImplementationViaProperties(pluginClass, dynamicProperties);
        if (p != null) return p;        
        // 2
        return findService(pluginClass, classLoader);
    }