asyncio-extensions

Create a fully-functional mini-app that serves as a personal task manager using the Python package 'asyncio-extensions'. This app should allow users to add, edit, delete, and mark tasks as completed. Additionally, it should have the ability to periodically check for any overdue tasks and notify the user via email or SMS.

### Features:
1. **Task Management**
   - Add new tasks with due dates and descriptions.
   - Edit existing tasks.
   - Mark tasks as completed.
   - Delete tasks.
2. **Notification System**
   - Send notifications when tasks become overdue.
   - Notifications can be sent via email or SMS.
3. **User Interface**
   - Simple command-line interface for adding/editing/deleting tasks.
   - Real-time updates on task status.
4. **Data Persistence**
   - Tasks should persist even after the app is closed.
   - Use SQLite for storing tasks.
5. **Concurrency and Performance**
   - Utilize 'asyncio-extensions' to handle concurrent task operations efficiently.
   - Ensure smooth operation even with a large number of tasks.

### Utilization of 'asyncio-extensions':
- Use the 'asyncio-extensions' package to manage asynchronous operations such as sending notifications and checking for overdue tasks. Specifically, implement a background task that periodically checks for overdue tasks using the package's scheduling capabilities. Also, use its concurrency features to ensure that adding, editing, deleting, and marking tasks as completed can be done concurrently without blocking other operations.