##### async_playwright()
- `async_playwright()`
- 一个创建异步 class Playwright 上下文管理器对象的顶层API
- 开始时返回异步 class Playwright 实例
- 结束时终止此异步 class Playwright 实例
```python
import asyncio
from playwright.async_api import async_playwright, Playwright
async def run(playwright: Playwright):
chromium = playwright.chromium # or "firefox" or "webkit".
browser = await chromium.launch()
page = await browser.new_page()
await page.goto("http://example.com")
# other actions...
await browser.close()
async def main():
async with async_playwright() as playwright:
await run(playwright)
asyncio.run(main())
```