dealing with null safety issues

LateInitializationError: Field '_endpointsData@26447715' has not been initialized

have this issue at the moment

Syncing files to device Android SDK built for x86...
lib/app/ui/dashboard.dart:22:17: Error: Field '_endpointsData' should be initialized because its type 'EndpointsData' doesn't allow null.
- 'EndpointsData' is from 'package:coronavirus_rest_api_flutter/app/repositories/endpoints_data.dart' ('lib/app/repositories/endpoints_data.dart').
EndpointsData _endpointsData;
^^^^^^^^^^^^^^
Error: Cannot run with sound null safety, because the following dependencies
don't support null safety:

Start at lib/app/ui/dashboard.dart:22 and inspect how _endpointsData is declared and used, then read lib/app/repositories/endpoints_data.dart and check the reported dependency compatibility. Confirm the app can run with sound null safety without the initialization and dependency errors.

Written by the indexing model from the issue text.