@Override
    public TimestampedValue<V> next() {
      Entry<TimeSeriesKey<K>, V> next = wrappedIterator.next();
      return new TimestampedValue<>(next.getValue(), next.getKey().getTimestamp());
    }
Creates a {@link TimeSeriesStoreImpl} in append mode.

@param kvStore the backing kv store to use
samza-core/src/main/java/org/apache/samza/operators/impl/store/TimeSeriesStoreImpl.java