private boolean willCurrentBlobExceedRecordLimit() {
    return (recordsInCurrentBlob + 1) > maxRecordsPerBlob;
  }
This method closes all DataFileWriters and output streams associated with all the blobs created.
flush should be explicitly called before close.
{@inheritDoc}
@throws IllegalStateException when closing a closed writer
@throws SamzaException if underlying DataFileWriter.close fails
samza-azure/src/main/java/org/apache/samza/system/azureblob/avro/AzureBlobAvroWriter.java