@Override
    public long estimateMemoryUsageBytes() {
      return Stream.of(ints).mapToLong(AppendStore::estimateMemoryUsageBytes).sum();
    }
An array longs that uses 4 bytes to represent each long by using a list of {@link Ints} arrays. Only suitable for
values less than ~20 billion (i.e. OSM node IDs)
planetiler-core/src/main/java/com/onthegomap/planetiler/collection/AppendStore.java