message: Cleared timeout on unmount
diff: @@ -7,6 +7,7 @@ type SceneProps = { crumb: number, sceneKey: string, renderScene: (state: State,
  type SceneState = { navigationEvent: NavigationEvent };
  class Scene extends React.Component<SceneProps, SceneState> {
  + private timer: number;
  constructor(props) {
  super(props);
  this.state = {navigationEvent: null};
  @@ -21,7 +22,7 @@ class Scene extends React.Component<SceneProps, SceneState> {
  componentDidMount() {
  var {stateNavigator} = this.props.navigationEvent;
  stateNavigator.onBeforeNavigate(this.onBeforeNavigate);
  - if (this.fluentPeekable()) setTimeout(this.peekNavigate);
  + if (this.fluentPeekable()) this.timer = setTimeout(this.peekNavigate);
  }
  static getDerivedStateFromProps(props: SceneProps, {navigationEvent: prevNavigationEvent}: SceneState) {
  var {crumb, navigationEvent} = props;
  @@ -38,11 +39,12 @@ class Scene extends React.Component<SceneProps, SceneState> {
  return navigationEvent !== this.state.navigationEvent || this.fluentPeekable();
  }
  componentDidUpdate() {
  - if (this.fluentPeekable()) setTimeout(this.peekNavigate);
  + if (this.fluentPeekable()) this.timer = setTimeout(this.peekNavigate);
  }
  componentWillUnmount() {
  var {stateNavigator} = this.props.navigationEvent;
  stateNavigator.offBeforeNavigate(this.onBeforeNavigate);
  + clearTimeout(this.timer);
  }
  fluentPeekable() {
  var {navigationEvent, crumb} = this.props;
  