message: improve temporal multi-sample rendering
  don't render all when spinning
  only render all when explicitely requested (new allowMulti arg)
diff: @@ -360,12 +360,12 @@ namespace Canvas3D {
  helper.handle.scene.update(void 0, true);
  helper.camera.scene.update(void 0, true);
  const prevPickDirty = pickHelper.dirty;
  - draw(true);
  + draw(true, true);
  pickHelper.dirty = prevPickDirty; // marking does not change picking buffers
  }
  }
  - function render(force: boolean) {
  + function render(force: boolean, allowMulti: boolean) {
  if (webgl.isContextLost) return false;
  let resized = false;
  @@ -396,7 +396,7 @@ namespace Canvas3D {
  }
  if (MultiSamplePass.isEnabled(p.multiSample)) {
  - if (!cameraChanged) {
  + if (!cameraChanged && allowMulti && !controls.props.spin) {
  while (!multiSampleHelper.render(renderer, cam, scene, helper, true, p.transparentBackground, p));
  } else {
  multiSampleHelper.render(renderer, cam, scene, helper, true, p.transparentBackground, p);
  @@ -416,9 +416,9 @@ namespace Canvas3D {
  let currentTime = 0;
  let drawPaused = false;
  - function draw(force?: boolean) {
  + function draw(force?: boolean, allowMulti?: boolean) {
  if (drawPaused) return;
  - if (render(!!force) && notifyDidDraw) {
  + if (render(!!force, !!allowMulti) && notifyDidDraw) {
  didDraw.next(now() - startTime as now.Timestamp);
  }
  }
  