public String primaryOffsetsTopic() {
        return primaryOffsetsTopic;
    }
Builds an offset store that uses a connector-specific offset topic as the primary store, and no secondary store.

@param loggingContext a {@link Supplier} for the {@link LoggingContext} that should be used
                      for messages logged by this offset store; may not be null, and may never return null
@param connectorStore the connector-specific offset store; may not be null
@param connectorOffsetsTopic the name of the connector-specific offset topic; may not be null
@param connectorStoreAdmin the topic admin to use for the connector-specific offset topic; may not be null
@return an offset store for the connector backed solely by the connector-specific offset topic; never null
connect/runtime/src/main/java/org/apache/kafka/connect/storage/ConnectorOffsetBackingStore.java