public interface RequestInfo {
  
  /* @return the request header that contains information such as API key, API version, client ID and etc.
   */
  public RequestHeader getHeader();
  
  /* @return IP address of the client that made this request
   */
  public InetAddress getClientAddress();
  
  /* @return principal of the client that made this request
   */
  public KafkaPrincipal getPrincipal();
  
  /* @return size in bytes of the body of this request
   */
  public int getBodySize();
  
  /* This method should only be invoked if the request is of type ApiKeys.PRODUCE. Otherwise, an exception is thrown.
   * @return a map of topic name to the number of bytes that are supposed to be produced to this topic in this request
   */
  public Map<String, Long> getProduceToTopicSizeInBytes();

  /* This method should only be invoked if the request is of type ApiKeys.PRODUCE. Otherwise, an exception is thrown.
   * @return a map of topic name to the number of records that are supposed to be produced to this topic in this request
   */
  public Map<String, Long> getProduceToTopicRecordCount();
}

public interface ResponseInfo {
  /* @return a map of error to its count of occurrence.
   */
  public Map<Errors, Integer> getErrorCounts();

  /* This method should only be invoked if the response is of type ApiKeys.FETCH. Otherwise, an exception is thrown.
   * @return a map of topic partition to the number of bytes that are fetched from this topic partition.
   */
  public Map<TopicPartition, Long> getFetchFromTopicPartitionSizeInBytes();
}

public class RequestAdapter implements RequestInfo {


	public RequestAdapter(RequestChannel.Request request) {
		// ...
	}
	// ...
}

public class ResponseAdapter implements ResponseInfo {


	public ResponseAdapter(AbstractResponse response) {
		// ...
	}
	// ...
}