public int getThreadPoolSize() {
    Optional<String> autosizingContainerThreadPoolSize = Optional.ofNullable(get(
        JOB_AUTOSIZING_CONTAINER_THREAD_POOL_SIZE));
    if (getAutosizingEnabled() && autosizingContainerThreadPoolSize.isPresent()) {
      return Integer.parseInt(autosizingContainerThreadPoolSize.get());
    } else {
      return getInt(JOB_CONTAINER_THREAD_POOL_SIZE, 0);
    }
  }
Return the value of JOB_CONTAINER_THREAD_POOL_SIZE if autosizing is not enabled,
otherwise returns the value of JOB_AUTOSIZING_CONTAINER_THREAD_POOL_SIZE.
@return
samza-core/src/main/java/org/apache/samza/config/JobConfig.java