public Map<String, StorageEngine> getAllStores(TaskName taskName) {
    if (!isStarted) {
      throw new SamzaException(String.format(
          "Attempting to access stores for task %s before ContainerStorageManager is started.", taskName));
    }
    return this.taskStores.get(taskName);
  }
Get all {@link StorageEngine} instance used by a given task.
@param taskName the task name, all stores for which are desired.
@return map of stores used by the given task, indexed by storename
samza-core/src/main/scala/org/apache/samza/storage/ContainerStorageManager.java