RuntimeError: Event loop is closed

### Describe the bug

There is no problem using asyncmy
There is a "RuntimeError: Event loop is closed" error when using aiomysql

Am I using it incorrectly? What's wrong?

### To Reproduce

```python
import asyncio
from sqlmodel import SQLModel, Field
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import sessionmaker

class User(SQLModel, table=True):
id: int = Field(default=None, primary_key=True)

DATABASE_URL = "mysql+asyncmy://root:@localhost:4000/test" ## ✅
DATABASE_URL = "mysql+aiomysql://root:@localhost:4000/test" ## ❌
engine = create_async_engine(DATABASE_URL, echo=True)

AsyncSessionLocal = sessionmaker(engine, expire_on_commit=False, class_=AsyncSession)

async def create_db_and_tables():
async with engine.begin() as conn:
await conn.run_sync(SQLModel.metadata.create_all)

async def main():
await create_db_and_tables()

if __name__ == "__main__":
asyncio.run(main())
```

### Expected behavior

Don't happen `RuntimeError: Event loop is closed`

### Logs/tracebacks

```python-traceback
There is no problem using asyncmy
There is a "RuntimeError: Event loop is closed" error when using aiomysql
```

### Python Version
Python 3.12.7

### aiomysql Version
0.2.0

### PyMySQL Version
1.1.0

### SQLAlchemy Version
2.0.36

### OS
macOS

### Database type and version
8.0.11-TiDB-v7.5.1

### Additional context

_No response_

### Code of Conduct

- [X] I agree to follow the aio-libs Code of Conduct