@Override
  public boolean startBlobStore(PartitionId id) {
    try {
      lock.writeLock().lock();
      if (partitionToStore.get(id) != null) {
        partitionToStore.get(id).start();
        return true;
      }
    } finally {
      lock.writeLock().unlock();
    }
    return false;
  }
Returning null because this will not be used as part of CloudStorageManager Implementation.
Implementation will be added if needed.
ambry-cloud/src/main/java/com/github/ambry/cloud/CloudStorageManager.java