message: Properly provides item.__id to keyExtractor
diff: @@ -148,7 +148,7 @@ export class AllArtists extends React.Component<Props, State> {
  }
  }}
  sections={this.state.sections}
  - keyExtractor={(item, index) => item + index}
  + keyExtractor={item => item.__id}
  />
  )
  }
  