@Override
    void poll(RequestRegistrationCallback<PutOperation> requestRegistrationCallback) {
      if (isBuilding() && chunkFillingCompletedSuccessfully
          && indexToChunkIdsAndChunkSizes.size() == getNumDataChunks()) {
        finalizeMetadataChunk();
      }
      if (isReady()) {
        super.poll(requestRegistrationCallback);
      }
    }
Notify for the creation of the first chunk. To be called after the overall operation is completed if the overall
blob is composite. If no first chunk was put successfully, this will do nothing.
ambry-router/src/main/java/com/github/ambry/router/PutOperation.java