onst onViewRef = React.useRef((viewableItems)=> {
      console.log(viewableItems)
      // Use viewable items in state or as intended
  })
  const viewConfigRef = React.useRef({ viewAreaCoveragePercentThreshold: 50 })


 index.toString()}
      viewabilityConfig={viewConfigRef.current}
      renderItem={({ item, index }) => { ... }}
/>