@Override
  public String toString() {
    return "ContainerModel [id=" + id + ", tasks=" + tasks + "]";
  }
Returns a map for all tasks in this container. The keys are the names of the tasks in the container and the values
are the corresponding {@link TaskModel}s.
@return map from {@link TaskName} to {@link TaskModel}
samza-api/src/main/java/org/apache/samza/job/model/ContainerModel.java