vb.baseVal.x = u.x - (u.x - vb.baseVal.x) * (w2 / w1);
    vb.baseVal.y = u.y - (u.y - vb.baseVal.y) * (h2 / h1);
  }

  function handleWheel(e) {
    if (e.deltaY == 0) return;
    // Change scale factor by 1.1 or 1/1.1
    rescale(currentScale * (e.deltaY < 0 ? 1.1 : (1/1.1)),
            toSvg(e.offsetX, e.offsetY));
  }

  function setMode(m) {
    mode = m;
    touchid = null;
    touchid2 = null;
  }

	var logFiltered string
	if !req.Delta.IsEmpty() && !requiresResourceNamesModification(w.TypeUrl) {
		// Some types opt out of this and natively handle req.Delta
		logFiltered = " filtered:" + strconv.Itoa(len(w.ResourceNames)-len(req.Delta.Subscribed))
		w = &model.WatchedResource{
			TypeUrl:       w.TypeUrl,
			ResourceNames: req.Delta.Subscribed.UnsortedList(),
		}
	}

	var res model.Resources

	if config == nil {
		config = &DeltaADSConfig{}
	}
	delta := NewDelta(discoveryAddr, config, opts...)
	delta.cfg.BackoffPolicy = backoffPolicy
	return delta
}

func typeName[T proto.Message]() string {
	ft := new(T)
	return resource.APITypePrefix + string((*ft).ProtoReflect().Descriptor().FullName())
}

			sum += delta(r0, r1)
			sum += delta(g0, g1)
			sum += delta(b0, b1)
			n += 3
		}
	}
	return sum / n
}

// lzw.NewWriter wants an interface which is basically the same thing as gif's
// writer interface.  This ensures we're compatible.
var _ writer = blockWriter{}

var testCase = []struct {
	filename  string
	tolerance int64
}{
	{"../testdata/video-001.png", 1 << 12},
	{"../testdata/video-001.gif", 0},

	t.Parallel()
	const Count = 10
	Delta := 100 * Millisecond
	if testing.Short() {
		Delta = 10 * Millisecond
	}
	t0 := Now()
	for i := 0; i < Count; i++ {
		<-After(Delta)
	}
	t1 := Now()
	d := t1.Sub(t0)
	target := Delta * Count
	if d < target*9/10 {
		t.Fatalf("%d ticks of %s too fast: took %s, expected %s", Count, Delta, d, target)
	}
	if !testing.Short() && d > target*30/10 {

	dx, dy := r.Dx(), r.Dy()
	d0 := dst.PixOffset(r.Min.X, r.Min.Y)
	s0 := src.PixOffset(sp.X, sp.Y)
	var (
		ddelta, sdelta int
		i0, i1, idelta int
	)
	if r.Min.Y < sp.Y || r.Min.Y == sp.Y && r.Min.X <= sp.X {
		ddelta = dst.Stride
		sdelta = src.Stride
		i0, i1, idelta = 0, dx*4, +4
	} else {
		// If the source start point is higher than the destination start point, or equal height but to the left,

// Returns list of goroutines that become runnable.
// delay < 0: blocks indefinitely
// delay == 0: does not block, just polls
// delay > 0: block for up to that many nanoseconds
func netpoll(delay int64) (gList, int32) {
	if portfd == -1 {
		return gList{}, 0
	}

	var wait *timespec
	var ts timespec
	if delay < 0 {
		wait = nil
	} else if delay == 0 {
		wait = &ts
	} else {
		ts.setNsec(delay)

	}
}

// heapStatsDelta contains deltas of various runtime memory statistics
// that need to be updated together in order for them to be kept
// consistent with one another.
type heapStatsDelta struct {
	// Memory stats.
	committed       int64 // byte delta of memory committed
	released        int64 // byte delta of released memory generated
	inHeap          int64 // byte delta of memory placed in the heap

//     Disable notifications for fd. Return an errno value.
//
// func netpoll(delta int64) (gList, int32)
//     Poll the network. If delta < 0, block indefinitely. If delta == 0,
//     poll without blocking. If delta > 0, block for up to delta nanoseconds.
//     Return a list of goroutines built by calling netpollready,
//     and a delta to add to netpollWaiters when all goroutines are ready.

		if dir == model.TrafficDirectionInbound {
			// Append all inbound clusters because in both stow/delta we always build all inbound clusters.
			// In reality, the delta building is only for outbound clusters. We need to revist here once we support delta for inbound.
			// So deletedClusters.Difference(builtClusters) would give us the correct deleted inbound clusters.
			deletedClusters.Insert(cluster)