public void replay(PartitionChangeRecord record) {
        PartitionRegistration partition = partitionChanges.get(record.partitionId());
        if (partition == null) {
            partition = image.partitions().get(record.partitionId());
            if (partition == null) {
                throw new RuntimeException("Unable to find partition " +
                    record.topicId() + ":" + record.partitionId());
            }
        }
        partitionChanges.put(record.partitionId(), partition.merge(record));
    }
Represents changes to a topic in the metadata image.
metadata/src/main/java/org/apache/kafka/image/TopicDelta.java