case on which you can see the issue with async operations inside handler

src/index.ts

@@ -3,24 +3,43 @@ import { track } from './track'
 import { getOrderPayload, getPageviewPayload } from './payload'
 
 export default function (manager: Manager, settings: ComponentSettings) {
-  manager.addEventListener('pageview', event => {
-    return track(event, getPageviewPayload(event, settings))
+  manager.addEventListener('pageview', async event => {
+    console.log('Event pageview: ' + JSON.stringify(event))
+
+    const res = await track(event, getPageviewPayload(event, settings))
+
+    console.log(`--> and here is another log we wont see`, 123)
+
+    console.log(
+      `--> this track() wont be invoked, at least i didnt see the log inside the fn second time`
+    )
+    const res2 = await track(event, getPageviewPayload(event, settings))
+
+    console.log(`--> no log for res2`, res2)
+
+    return res
   })
 
-  manager.addEventListener('ecommerce', event => {
+  manager.addEventListener('ecommerce', async event => {
+    console.log('Event ecommerce: ' + JSON.stringify(event))
     const action =
       event.name || event.payload.name || event.payload.ecommerce.name
 
     switch (action) {
       case 'Product Viewed': {
-        return track(event, getPageviewPayload(event, settings))
+        const res = await track(event, getPageviewPayload(event, settings))
+        console.log('res', res)
+        return res
       }
 
       case 'Order Completed': {
-        return track(event, getOrderPayload(event, settings))
+        const res = await track(event, getOrderPayload(event, settings))
+        console.log('res', res)
+        return res
       }
 
       default: {
+        console.log('Wrong action', action)
         return
       }
     }

src/track.ts

@@ -2,15 +2,24 @@ import { MCEvent } from '@managed-components/types'
 import { DemaPayload } from './types'
 
 export const track = async (event: MCEvent, payload: DemaPayload) => {
+  console.log('Run track', event, payload)
+
   const url = new URL('https://tracker.dema.ai/track.js')
 
   for (const [key, value] of Object.entries(payload)) {
     url.searchParams.set(key, value)
   }
 
-  return fetch(url.toString(), {
-    headers: {
-      'User-Agent': event.client.userAgent,
-    },
-  })
+  // console.log('Track: ' + url.toString())
+
+  // let's use API that works 100% just for testing
+  console.log('Track:', 'jsonplaceholder')
+
+  // return fetch(url.toString(), {
+  return fetch('https://jsonplaceholder.typicode.com/posts')
+    .then(response => response.json())
+    .then(response => {
+      console.log('--> Here is the response we wont see', response)
+      return response
+    })
 }