docs: update NOTES

Author: cybex-dev

NOTES.md

@@ -15,3 +15,10 @@ Future work may include:
 - Audio & VIDEO handling
 - Integration with native callkit frameworks
 
+### Regarding imports
+
+So, this is a tricky one I hope to resolve soon. For now, one should use the web_callkit_web.dart import instead of the web_callkit.dart import. 
+
+This is because the web_callkit.dart import is a stub for the web_callkit_web.dart import. This is due to multiple instances are created when calling `WebCallKit.instance` in a web OS environment. Even though a `WebCallKitWeb` object is created and registered with the plugin, it seems the Flutter still prefers the MethodChannel file filled with stubs.
+
+If you have a solution for this, please let me know. I would love to hear it or submit a PR addressing the issue. Note, the issue crops up in child dependencies of the plugin, e.g. [twilio_voice](https://pub.dev/packages/twilio_voice) but is not found in the example project.