message: Froze scene contents if not current scene
  Can't do the freeze in NavigationStack because still need to render scene. If fluently navigating from A to A -> B -> C -> D then need to render B (and D) so that, e.g., the animations are set up
diff: import React, { ReactNode } from 'react';
  +import { Freeze } from 'react-freeze';
  import { requireNativeComponent, Platform, StyleSheet } from 'react-native';
  import { StateNavigator, StateContext, State, Crumb } from 'navigation';
  import { NavigationContext, NavigationEvent } from 'navigation-react';
  @@ -136,7 +137,7 @@ class Scene extends React.Component<SceneProps, SceneState> {
  }
  render() {
  var {navigationEvent} = this.state;
  - var {crumb, title, sceneKey, popped, navigationEvent: {stateNavigator}} = this.props;
  + var {crumb, title, sceneKey, freezable, popped, navigationEvent: {stateNavigator}} = this.props;
  var {crumbs} = stateNavigator.stateContext;
  var {state, data} = navigationEvent ? navigationEvent.stateNavigator.stateContext : crumbs[crumb];
  return (
  @@ -148,7 +149,9 @@ class Scene extends React.Component<SceneProps, SceneState> {
  onPopped={() => popped(sceneKey)}>
  <BackButton onPress={this.handleBack} />
  <NavigationContext.Provider value={navigationEvent}>
  + <Freeze freeze={freezable && crumbs.length !== crumb}>
  {navigationEvent && this.props.renderScene(state, data)}
  + </Freeze>
  </NavigationContext.Provider>
  </NVScene>
  );
  