How to use vue2-leaflet in vue3 App, what changes need to be made?

I'm adding an Openstreetmap component. Newbie, straight to Vue3 (do not ask me to start from Vue2),

MapLeaflet.vue : I took the code from here: https://vue2-leaflet.netlify.app/examples/simple.html

And tried to modify to suite vue3, creating setup(), move functions etc. However looks like the return statement and some imports need to be further tweaked. What should I change in this vue2-leaflet to transform it to work in vue3?

<template>
  <div style="height: 500px; width: 100%">
    <div style="height: 200px overflow: auto;">
      <p>First marker is placed at {{ withPopup.lat }}, {{ withPopup.lng }}</p>
      <p>Center is at {{ currentCenter }} and the zoom is: {{ currentZoom }}</p>
      <button @click="showLongText">
        Toggle long popup
      </button>
      <button @click="showMap = !showMap">
        Toggle map
      </button>
    </div>
    <l-map
      v-if="showMap"
      :zoom="zoom"
      :center="center"
      :options="mapOptions"
      style="height: 80%"
      @update:center="centerUpdate()"
      @update:zoom="zoomUpdate()"
    >
      <l-tile-layer
        :url="url"
        :attribution="attribution"
      />
      <l-marker :lat-lng="withPopup">
        <l-popup>
          <div @click="innerClick()">
            I am a popup
            <p v-show="showParagraph">
              Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque
              sed pretium nisl, ut sagittis sapien. Sed vel sollicitudin nisi.
              Donec finibus semper metus id malesuada.
            </p>
          </div>
        </l-popup>
      </l-marker>
      <l-marker :lat-lng="withTooltip">
        <l-tooltip :options="{ permanent: true, interactive: true }">
          <div @click="innerClick">
            I am a tooltip
            <p v-show="showParagraph">
              Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque
              sed pretium nisl, ut sagittis sapien. Sed vel sollicitudin nisi.
              Donec finibus semper metus id malesuada.
            </p>
          </div>
        </l-tooltip>
      </l-marker>
    </l-map>
  </div>
</template>

<script>
import { latLng } from "leaflet";
import { LMap, LTileLayer, LMarker, LPopup, LTooltip } from "vue2-leaflet";

export default {
  name: "Example",
  components: {
    LMap,
    LTileLayer,
    LMarker,
    LPopup,
    LTooltip
  },
  setup() {
    
    function zoomUpdate(zoom) {
      currentZoom = zoom;
    }
    function centerUpdate(center) {
      currentCenter = center;
    }
    function showLongText() {
      showParagraph = !this.showParagraph;
    }
    function innerClick() {
      alert("Click!");
    }

    return {
      zoom: 13,
      center: latLng(47.41322, -1.219482),
      url: 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
      attribution:
        '&copy; <a href="http://osm.org/copyright">OpenStreetMap</a> contributors',
      withPopup: latLng(47.41322, -1.219482),
      withTooltip: latLng(47.41422, -1.250482),
      currentZoom: 11.5,
      currentCenter: latLng(47.41322, -1.219482),
      showParagraph: false,
      mapOptions: {
        zoomSnap: 0.5
      },
      showMap: true
    };
    
  },
  methods: {

  }
};
</script>