// For both uvdelta and pcdelta, the common case (~70%)
	// is that they are a single byte. If so, avoid calling readvarint.
	uvdelta := uint32(p[0])
	if uvdelta == 0 && !first {
		return nil, false
	}
	n := uint32(1)
	if uvdelta&0x80 != 0 {
		n, uvdelta = readvarint(p)
	}
	*val += int32(-(uvdelta & 1) ^ (uvdelta >> 1))
	p = p[n:]

	pcdelta := uint32(p[0])

			if int64(nextpc) == int64(len(d.ldr.Data(fn))) {
				nextpc--
				if nextpc < pcsp.PC {
					continue
				}
			}

			spdelta := int64(pcsp.Value)
			if !haslr {
				// Return address has been pushed onto stack.
				spdelta += int64(d.arch.PtrSize)
			}

			if haslr && !fi.TopFrame() {
				// TODO(bryanpkc): This is imprecise. In general, the instruction

		frame.lr = 0
	} else if flag&abi.FuncFlagSPWrite != 0 && (!innermost || u.flags&(unwindPrintErrors|unwindSilentErrors) != 0) {
		// The function we are in does a write to SP that we don't know
		// how to encode in the spdelta table. Examples include context
		// switch routines like runtime.gogo but also any code that switches
		// to the g0 stack to run host C code.
		// We can't reliably unwind the SP (we might not even be on

func step(p *[]byte, pc *uint64, val *int32, first bool, arch *sys.Arch) bool {
	uvdelta := readvarint(p)
	if uvdelta == 0 && !first {
		return false
	}
	if uvdelta&1 != 0 {
		uvdelta = ^(uvdelta >> 1)
	} else {
		uvdelta >>= 1
	}
	vdelta := int32(uvdelta)
	pcdelta := readvarint(p) * uint32(arch.MinLC)
	*pc += uint64(pcdelta)
	*val += vdelta
	return true
}

	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())
}

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.

    double x1 = 1.2;
    double y1 = 3.4;
    double xDelta = 5.6;
    double yDelta = 7.8;
    LinearTransformation transformation =
        LinearTransformation.mapping(x1, y1).and(x1 + xDelta, y1 + yDelta);
    assertDiagonalLinearTransformation(transformation, x1, y1, xDelta, yDelta);
  }

  public void testMappingAnd_horizontal() {
    double x1 = 1.2;
    double xDelta = 3.4;
    double y = 5.6;

    double x1 = 1.2;
    double y1 = 3.4;
    double xDelta = 5.6;
    double yDelta = 7.8;
    LinearTransformation transformation =
        LinearTransformation.mapping(x1, y1).and(x1 + xDelta, y1 + yDelta);
    assertDiagonalLinearTransformation(transformation, x1, y1, xDelta, yDelta);
  }

  public void testMappingAnd_horizontal() {
    double x1 = 1.2;
    double xDelta = 3.4;
    double y = 5.6;

    assertThat(transformation.transform(x1 + xDelta)).isWithin(ALLOWED_ERROR).of(y1 + yDelta);
    assertThat(transformation.inverse().transform(y1)).isWithin(ALLOWED_ERROR).of(x1);
    assertThat(transformation.inverse().transform(y1 + yDelta))
        .isWithin(ALLOWED_ERROR)
        .of(x1 + xDelta);
    assertThat(transformation.slope()).isWithin(ALLOWED_ERROR).of(yDelta / xDelta);