@Override
  public String toString() {
    return "BlobStoreControlAdminRequest[ClientId=" + clientId + ", CorrelationId=" + correlationId
        + ", BlobStoreControlAction=" + storeControlAction + ", NumReplicasCaughtUpPerPartition="
        + numReplicasCaughtUpPerPartition + ", PartitionId=" + getPartitionId() + "]";
  }
@return the least number of replicas that have to be within 0 byte for each partition.
ambry-protocol/src/main/java/com/github/ambry/protocol/BlobStoreControlAdminRequest.java