public void checkIsAllocated() {
    int originalBits =
        AddressableMemoryManager.readIntVolatile(memoryAddress + REF_COUNT_OFFSET);
    if ((originalBits & MAGIC_MASK) != MAGIC_NUMBER) {
      throw new IllegalStateException(
          "It looks like this off heap memory was already freed. rawBits="
              + Integer.toHexString(originalBits));
    }
  }
Throw an exception if this chunk is not allocated
geode-core/src/main/java/org/apache/geode/internal/offheap/OffHeapStoredObject.java