message: Forwarded ref to BottomAppBar
  Couldn't set ref for functional components so forwardedRef. Better than turning into class level component because the ref should point at the native BottomAppBar (think it will have to when Fabric lands)
diff: -import React from 'react';
  +import React, { forwardRef } from 'react';
  import { Platform, Image, StyleSheet, requireNativeComponent } from 'react-native';
  -const BottomAppBar = ({ navigationImage, overflowImage, children, style, ...props }: any) => {
  +const BottomAppBar = forwardRef(({ navigationImage, overflowImage, children, style, ...props }: any, ref) => {
  return (
  <NVBottomAppBar
  + ref={ref}
  navigationImage={Image.resolveAssetSource(navigationImage)}
  overflowImage={Image.resolveAssetSource(overflowImage)}
  style={styles.toolbar}
  @@ -11,7 +12,7 @@ const BottomAppBar = ({ navigationImage, overflowImage, children, style, ...prop
  {children}
  </NVBottomAppBar>
  );
  -}
  +})
  var NVBottomAppBar = requireNativeComponent<any>('NVBottomAppBar', null);
  