@get("/foo")
async def foo(db_pool: Pool, db_connection: Connection) -> Stream:
    stream_id = await db_connection.fetchval(
        """insert into toto(stream) values ('') returning id"""
    )
    print(stream_id)

    async def chunks(num, stream_id):
        async with db_pool.acquire() as conn:
            try:
                for i in range(num):
                    chunk = f"chunk #{i}\n"
                    yield chunk
                    await asyncio.sleep(0.5)
                    update = await conn.execute(
                        f"update toto set stream = '{i}' where id={stream_id}"
                    )
                    print(update)

            except CancelledError as e:
                print(str(e))
                with CancelScope(shield=True):
                    delete = await conn.execute(f"delete from toto where id={id}")
                    print(delete)
		raise
            finally:
                print("end")
    return Stream(chunks(10, stream_id))