presto-accumulo/src/main/java/io/prestosql/plugin/accumulo/io/AccumuloPageSink.java/AccumuloPageSink/flush
class AccumuloPageSink:    private void flush()
    {
        try {
            if (indexer.isPresent()) {
                indexer.get().flush();
                // MetricsWriter is non-null if Indexer is present
            }
            writer.flush();
        }
        catch (MutationsRejectedException e) {
            throw new PrestoException(UNEXPECTED_ACCUMULO_ERROR, "Mutation rejected by server on flush", e);
        }
    }