@Override
    MessageFormatFlags getOperationFlag() {
      return options.getBlobOptions.getOperationType() == GetBlobOptions.OperationType.Data ? MessageFormatFlags.Blob
          : MessageFormatFlags.All;
    }
Return the {@link MessageFormatFlags} to associate with the first getBlob chunk operation.
@return {@link MessageFormatFlags#Blob} for {@link GetBlobOptions.OperationType#Data}, or
        {@link MessageFormatFlags#All} by default.
ambry-router/src/main/java/com/github/ambry/router/GetBlobOperation.java