How can Python handle 10,000 requests with one thread? Magic? No. The Event Loop.
The Chess Master Analogy
Imagine a Chess Master playing against 100 people simultaneously.
* He walks to Board 1, makes a move. (CPU work)
* The opponent thinks. (I/O wait)
* He walks to Board 2, makes a move.
He doesn't wait for Opponent 1 to finish thinking. He stays busy.
This is Asyncio.
Blocking the Loop
If the Chess Master stops at Board 1 and calculates Pi to a billion decimals... nobody else gets to play. The game freezes.
In Python:
async def bad_view():
time.sleep(10) # STOPS THE WORLD
Never block the loop. Use await asyncio.sleep(10).
Conclusion
Asyncio is cooperative multitasking. It relies on you, the developer, to be a good citizen and yield control when waiting.