void setGetBlobReadInfoTestCallback(Runnable getBlobReadInfoTestCallback) {
    this.getBlobReadInfoTestCallback = getBlobReadInfoTestCallback;
  }
This is only for test. Setting a getBlobReadInfo callback.
@param getBlobReadInfoTestCallback The callback to invoke when calling getBlobReadInfo method. It will be invoked
                                   right before we convert a PutValue into a BlobReadInfo.
ambry-store/src/main/java/com/github/ambry/store/PersistentIndex.java