@Override
  public void flush() {
    try {
      systemProducer.flush(SOURCE);
    } catch (Exception e) {
      LOG.error("Exception occurred when flushing the metadata store:", e);
      throw new SamzaException("Exception occurred when flushing the metadata store:", e);
    }
  }
An implementation of the {@link MetadataStore} interface where the metadata of the samza job is stored in coordinator stream.

This class is thread safe.

It is recommended to use {@link NamespaceAwareCoordinatorStreamStore}. This will enable the single CoordinatorStreamStore connection
to be shared by the multiple {@link NamespaceAwareCoordinatorStreamStore} instances.
samza-core/src/main/java/org/apache/samza/coordinator/metadatastore/CoordinatorStreamStore.java