```Python hl_lines="1"
async def get_burgers(number: int):
    # Do some asynchronous stuff to create the burgers
    return burgers
```

...↩️ `def`:

```Python hl_lines="2"
# This is not asynchronous
def get_sequential_burgers(number: int):
    # Do some sequential stuff to create the burgers
    return burgers
```

In this scenario of "fast food burgers with your crush", as there is a lot of waiting 🕙, it makes a lot more sense to have a concurrent system ⏸🔀⏯.

This is the case for most of the web applications.

Many, many users, but your server is waiting 🕙 for their not-so-good connection to send their requests.

And then waiting 🕙 again for the responses to come back.

```Python hl_lines="1"
async def get_burgers(number: int):
    # Do some asynchronous stuff to create the burgers
    return burgers
```

...`def`를 사용하는 대신:

```Python hl_lines="2"
# This is not asynchronous
def get_sequential_burgers(number: int):
    # Do some sequential stuff to create the burgers
    return burgers
```

```Python hl_lines="1"
async def get_burgers(number: int):
    # Do some asynchronous stuff to create the burgers
    return burgers
```

...en vez de `def`:

```Python hl_lines="2"
# This is not asynchronous
def get_sequential_burgers(number: int):
    # Do some sequential stuff to create the burgers
    return burgers
```

```Python hl_lines="1"
async def get_burgers(number: int):
    # Do some asynchronous stuff to create the burgers
    return burgers
```

...而不是 `def`:

```Python hl_lines="2"
# This is not asynchronous
def get_sequential_burgers(number: int):
    # Do some sequential stuff to create the burgers
    return burgers
```

使用 `async def`，Python 就知道在该函数中，它将遇上 `await`，并且它可以"暂停" ⏸ 执行该函数，直至执行其他操作 🔀 后回来。