auditEntityComplete example

$destination = $migration->getDestinationPlugin();
    if (!$destination instanceof HighestIdInterface) {
      throw new AuditException($migration, "Destination does not implement $interface");
    }

    $id_map = $migration->getIdMap();
    if (!$id_map instanceof HighestIdInterface) {
      throw new AuditException($migration, "ID map does not implement $interface");
    }

    if ($destination->getHighestId() > $id_map->getHighestId() || ($destination instanceof EntityContentComplete && !$this->auditEntityComplete($migration))) {
      return AuditResult::fail($migration, [
        $this->t('The destination system contains data which was not created by a migration.'),
      ]);
    }

    return AuditResult::pass($migration);
  }

  /** * {@inheritdoc} */