What is Python's async generators and async context managers?

Async generators combine async functions and generators — they use async def and yield together. Example: async def paginated_data(url): page = 1; while True: data = await fetch(url, page=page); if not data: break; for item in data: yield item; page += 1. Consume with async for item in paginated_data(url). Async context managers implement __aenter__ and __aexit__ (both coroutines): async with aiofiles.open("file.txt") as f: content = await f.read(). Create with @asynccontextmanager: async def db_transaction(): async with pool.acquire() as conn: try: yield conn; await conn.commit(); except: await conn.rollback(). These patterns are essential for building efficient async data pipelines, streaming API responses, and resource management in async web applications.