import org.apache.twill.kafka.client.KafkaConsumer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.Iterator;
<BUG>import java.util.List;
public final class MetricsMessageCallback implements KafkaConsumer.MessageCallback {
private static final Logger LOG = LoggerFactory.getLogger(MetricsMessageCallback.class);
private final DatumReader<MetricValues> recordReader;</BUG>
private final Schema recordSchema;

import org.apache.twill.kafka.client.KafkaConsumer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.TimeUnit;
public final class MetricsMessageCallback implements KafkaConsumer.MessageCallback {
private static final Logger LOG = LoggerFactory.getLogger(MetricsMessageCallback.class);
private static final ImmutableMap<String, String> METRICS_PROCESSOR_CONTEXT =
ImmutableMap.of(Constants.Metrics.Tag.NAMESPACE, Constants.SYSTEM_NAMESPACE,
Constants.Metrics.Tag.COMPONENT, "metrics.processor");
private final DatumReader<MetricValues> recordReader;
private final Schema recordSchema;
