message: Scaled logo when collapsing
diff: -import React, {useContext} from 'react';
  -import {StyleSheet, Text, Image, Platform, ScrollView, View} from 'react-native';
  +import React, {useContext, useState} from 'react';
  +import {StyleSheet, Text, Image, Platform, ScrollView, View, Animated} from 'react-native';
  import {NavigationContext} from 'navigation-react';
  import {NavigationBar, CoordinatorLayout, CollapsingBar} from 'navigation-react-native';
  import Tweets from './Tweets';
  @@ -7,10 +7,16 @@ import Tweets from './Tweets';
  export default ({timeline: {id, name, username, logo, bio,
  colors, followers, following, tweets}}) => {
  const {stateNavigator} = useContext(NavigationContext);
  + const [offset] = useState(new Animated.Value(0));
  + const diameter = offset.interpolate({
  + inputRange: [-64, 0],
  + outputRange: [60, 80],
  + })
  return (
  <CoordinatorLayout overlap={110}>
  <NavigationBar
  title={name}
  + onOffsetChanged={Animated.event([{nativeEvent:{offset}}])}
  navigationImage={require('./arrow.png')}
  barTintColor={Platform.OS === 'android' ? colors[0] : null}
  tintColor={Platform.OS === 'android' ? "#fff" : null}
  @@ -28,7 +34,9 @@ export default ({timeline: {id, name, username, logo, bio,
  contentInsetAdjustmentBehavior="automatic"
  style={styles.view}>
  <View>
  - <Image style={styles.logo} source={logo} />
  + <Animated.Image
  + source={logo}
  + style={[styles.logo, {width: diameter, height: diameter}]} />
  <Text style={styles.name}>{name}</Text>
  <Text>{username}</Text>
  <Text style={styles.bio}>{bio}</Text>
  @@ -52,8 +60,6 @@ const styles = StyleSheet.create({
  flex: 1,
  },
  logo: {
  - width: 80,
  - height: 80,
  borderRadius: 50,
  borderWidth: 4,
  borderColor: 'white',
  