continue
				}
				var v any
				if row.Counter != nil {
					cv := *row.Counter.Value
					key := toMetricKey(row, metric)
					if delta, f := m.deltas[key]; f {
						cv -= delta
					}
					v = cv
				} else if row.Gauge != nil {
					v = *row.Gauge.Value
				} else if row.Histogram != nil {
					v = row.Histogram
				}
				err := compare(v)

		return nil, model.DefaultXdsLogDetails, nil
	}
	clusters, logs := c.ConfigGenerator.BuildClusters(proxy, req)
	return clusters, logs, nil
}

// GenerateDeltas for CDS currently only builds deltas when services change. todo implement changes for DestinationRule, etc
func (c CdsGenerator) GenerateDeltas(proxy *model.Proxy, req *model.PushRequest,
	w *model.WatchedResource,

	_ = complex128(maxUint64)
)

// TODO(gri) find smaller deltas below

const delta32 = maxFloat32/(1 << 23)

const (
	_ float32 = - /* ERROR "overflow" */ (maxFloat32 + delta32)
	_ float32 = -maxFloat32
	_ float32 = maxFloat32
	_ float32 = maxFloat32 /* ERROR "overflow" */ + delta32

	_ = float32(- /* ERROR "cannot convert" */ (maxFloat32 + delta32))
	_ = float32(-maxFloat32)
	_ = float32(maxFloat32)

        "run again after ${formatDuration(executeNanoTime - now)}"
      } else {
        "scheduled after ${formatDuration(executeNanoTime - now)}"
      }
    }

    // Insert in chronological order. Always compare deltas because nanoTime() is permitted to wrap.
    var insertAt = futureTasks.indexOfFirst { it.nextExecuteNanoTime - now > delayNanos }
    if (insertAt == -1) insertAt = futureTasks.size
    futureTasks.add(insertAt, task)

  }

  /** Returns a new bias. */
  private fun adapt(
    delta: Int,
    numpoints: Int,
    first: Boolean,
  ): Int {
    var delta =
      when {
        first -> delta / DAMP
        else -> delta / 2
      }
    delta += (delta / numpoints)
    var k = 0
    while (delta > ((BASE - TMIN) * TMAX) / 2) {
      delta /= (BASE - TMIN)
      k += BASE
    }

issue:
  - 47949
releaseNotes:
  - |
    **Enabled** [Delta xDS](https://www.envoyproxy.io/docs/envoy/latest/api-docs/xds_protocol#incremental-xds) by default. See upgrade notes for more information.
upgradeNotes:
  - title: Delta xDS on by default
    content: |
      In previous versions, Istio used the "State of the world" xDS protocol to configure Envoy.

		// Both SotW and Delta did not respond, nothing to compare
		return
	}
	newByName := slices.GroupUnique(sotwRes, (*discovery.Resource).GetName)
	curByName := slices.GroupUnique(current, (*discovery.Resource).GetName)

	watched := sets.New(w.ResourceNames...)

	details := fmt.Sprintf("last:%v sotw:%v delta:%v-%v", len(current), len(sotwRes), len(deltaRes), len(deleted))
	wantDeleted := sets.New[string]()

	for i := from; i <= to; i += step {
		baseline := measureSqr(i, nruns, lower)
		testval := measureSqr(i, nruns, upper)
		pos := baseline > testval
		delta := baseline - testval
		percent := delta * 100 / baseline
		fmt.Printf("words = %3d deltaT = %10s (%4d%%) is %s better: %v", i, delta, percent, upper, pos)
		if i == from {
			initPos = pos
		}
		if threshold == 0 && pos != initPos {
			threshold = i

}

func (v *Float) appendJSON(b []byte) []byte {
	return strconv.AppendFloat(b, math.Float64frombits(v.f.Load()), 'g', -1, 64)
}

// Add adds delta to v.
func (v *Float) Add(delta float64) {
	for {
		cur := v.f.Load()
		curVal := math.Float64frombits(cur)
		nxtVal := curVal + delta
		nxt := math.Float64bits(nxtVal)
		if v.f.CompareAndSwap(cur, nxt) {
			return
		}
	}
}

// Set sets v to value.

func f(x *big, start int64) {
	if delta := inuse() - start; delta < 9<<20 {
		println("after alloc: expected delta at least 9MB, got: ", delta)
	}
	runtime.KeepAlive(x)
	x = nil
	if delta := inuse() - start; delta > 1<<20 {
		println("after drop: expected delta below 1MB, got: ", delta)
	}
	x = new(big)
	if delta := inuse() - start; delta < 9<<20 {
		println("second alloc: expected delta at least 9MB, got: ", delta)
	}