message: Calculated scroll y drag amount
diff: @@ -5,9 +5,30 @@ import SearchBar from './SearchBar';
  class CoordinatorLayout extends React.Component<any, any> {
  private ref: React.RefObject<any>;
  + private dragging = false;
  + private y = 0;
  constructor(props) {
  super(props);
  this.ref = React.createRef<any>();
  + this.onTouchStart = this.onTouchStart.bind(this);
  + this.onTouchMove = this.onTouchMove.bind(this);
  + this.onTouchEnd = this.onTouchEnd.bind(this);
  + this.onTouchCancel = this.onTouchCancel.bind(this);
  + }
  + onTouchStart({nativeEvent}) {
  + this.dragging = true;
  + this.y = nativeEvent.locationY;
  + }
  + onTouchMove({nativeEvent}) {
  + if (this.dragging) {
  + var deltaY = nativeEvent.locationY - this.y;
  + }
  + }
  + onTouchEnd() {
  + this.dragging = false;
  + }
  + onTouchCancel() {
  + this.dragging = false;
  }
  render() {
  var {overlap, children} = this.props;
  @@ -27,9 +48,10 @@ class CoordinatorLayout extends React.Component<any, any> {
  ref={this.ref}
  overlap={overlap}
  style={{flex: 1}}
  - onTouchStart={e => {
  - console.log(this.ref);
  - }}>
  + onTouchStart={this.onTouchStart}
  + onTouchMove={this.onTouchMove}
  + onTouchEnd={this.onTouchEnd}
  + onTouchCancel={this.onTouchCancel}>
  {clonedChildren}
  </NVCoordinatorLayout>
  {searchBar}
  