long sum = 0L;
    for (AtomicLong value : map.values()) {
      sum = sum + value.get();
    }
    return sum;
  }

  @LazyInit @CheckForNull private transient Map<K, Long> asMap;

  /** Returns a live, read-only view of the map backing this {@code AtomicLongMap}. */
  public Map<K, Long> asMap() {
    Map<K, Long> result = asMap;
    return (result == null) ? asMap = createAsMap() : result;
  }