@GwtIncompatible
  public static double mean(double... values) {
    checkArgument(values.length > 0, "Cannot take mean of 0 values");
    long count = 1;
    double mean = checkFinite(values[0]);
    for (int index = 1; index < values.length; ++index) {
      checkFinite(values[index]);
      count++;
      // Art of Computer Programming vol. 2, Knuth, 4.2.2, (15)
      mean += (values[index] - mean) / count;
    }
    return mean;

		},
	}
}

func (r *metacacheReader) checkInit() {
	if r.creator == nil || r.err != nil {
		return
	}
	r.err = r.creator()
	r.creator = nil
}

// peek will return the name of the next object.
// Will return io.EOF if there are no more objects.
// Should be used sparingly.
func (r *metacacheReader) peek() (metaCacheEntry, error) {
	r.checkInit()
	if r.err != nil {
		return metaCacheEntry{}, r.err