@Override
  public long startDefragmentation() {
    stats.incInt(defragmentationsInProgressId, 1);
    return DistributionStats.getStatTime();
  }
Constructs a MemoryAllocator for off-heap storage.

@return MemoryAllocator for off-heap storage
geode-core/src/main/java/org/apache/geode/internal/offheap/OffHeapStorage.java