apollo-mockserver/src/main/java/com/ctrip/framework/apollo/mockserver/EmbeddedApollo.java/EmbeddedApollo/addOrModifyProperty
class EmbeddedApollo:  public void addOrModifyProperty(String namespace, String someKey, String someValue) {
    if (addedOrModifiedPropertiesOfNamespace.containsKey(namespace)) {
      addedOrModifiedPropertiesOfNamespace.get(namespace).put(someKey, someValue);
    } else {
      Map<String, String> m = Maps.newConcurrentMap();
      m.put(someKey, someValue);
      addedOrModifiedPropertiesOfNamespace.put(namespace, m);
    }
  }