@Override
  public String toString() {
    return "ChunkInfo{" + "blobId='" + blobId + '\'' + ", chunkSizeInBytes=" + chunkSizeInBytes
        + ", expirationTimeInMs=" + expirationTimeInMs + ", reservedMetadataId=" + reservedMetadataId + '}';
  }
@return the reserved metadata id of the chunk.
ambry-api/src/main/java/com/github/ambry/router/ChunkInfo.java