public long totalNumRestored() {
            long totalNumRestored = 0L;
            for (final AtomicLong numRestored : changelogToTotalNumRestored.values()) {
                totalNumRestored += numRestored.get();
            }
            return totalNumRestored;
        }
Tracks the offsets and number of restored records on a per-partition basis.
Currently assumes only one store in the topology; you will need to update this
if it's important to track across multiple stores in a topology
streams/src/test/java/org/apache/kafka/streams/integration/utils/IntegrationTestUtils.java