Understanding and Running the asyncio Event Loop

This challenge will guide you through the fundamental process of creating and running an asyncio event loop in Python. Understanding how to manage asynchronous operations is crucial for building efficient, non-blocking applications, especially those involving network I/O or concurrent tasks.

Problem Description

Your task is to create a basic asyncio program that demonstrates the creation and execution of an event loop. You will need to define an asynchronous function, schedule it to run within the event loop, and then run the loop until that function completes.

Requirements:

1. Define an asynchronous function: Create a simple async def function (e.g., greet) that performs a basic operation, such as printing a message.
2. Get the event loop: Obtain the current event loop instance.
3. Schedule the coroutine: Schedule the execution of your asynchronous function as a task within the event loop.
4. Run the event loop: Execute the event loop until the scheduled task is complete.
5. Handle cleanup (optional but good practice): Ensure the event loop is properly closed after execution.

Expected Behavior:

When the script is run, it should print a message indicating that the asynchronous function has executed.

Edge Cases:

• What happens if the asynchronous function doesn't return a value?
• How does the event loop behave if there are no tasks scheduled? (While not directly tested in this basic challenge, it's good to be aware of).

Examples

Example 1:

Input:
(No direct input, the script is run)

Output:
Hello from the asyncio event loop!

Explanation:

The script defines an async def greet() function that prints "Hello from the asyncio event loop!". The event loop is created, greet() is scheduled, and the loop runs until greet() finishes, producing the output.

Example 2:

Input:
(No direct input, the script is run)

Output:
Starting async task...
Task completed.

Explanation:

This example shows a slightly more involved asynchronous function that prints a start and end message. The event loop manages the execution of this coroutine.

Constraints

• Python version: 3.7+ (to ensure asyncio.run() is available for simpler solutions, though manual loop management is also acceptable).
• No external libraries are allowed beyond the standard asyncio module.
• The solution should be a single Python script.

Notes

• The asyncio.run(coroutine()) function is the most straightforward way to run a single asynchronous entry point. It handles loop creation, running, and closing.
• Alternatively, you can manually get the loop (asyncio.get_event_loop()), schedule your coroutine (loop.create_task()), and then run the loop until a specific condition is met (e.g., loop.run_until_complete(task)), followed by loop.close(). This manual approach provides more control and is good to understand.
• Think about what makes a function "asynchronous" in Python.