fetch block when previous message not ack?

[suchen-sci]

Hi, team,

When I use following code, I find, when I call fetch method and not ack the message, the next call of fetch will be block, until the message is acked. I use AckExplicitPolicy as ack policy. So I am wondering how to solve this problem? That I can keep fetch messages even previous ones are not ack?

    async def init(self, settings: Settings):
        self.nc = await nats.connect(  # pyright: ignore reportUnknownMemberType
            settings.nats_urls()
        )
        self.js = self.nc.jetstream()  # pyright: ignore reportUnknownMemberType
        logger.info(f"create durable consumer {settings.serverless_id()}")

        self.consumer = await self.js.pull_subscribe(
            settings.subscribe_subject(),
            durable=settings.serverless_id(),
            stream=settings.stream_name(),
        )

    async def next(self):
        msgs = await self.consumer.fetch(1, timeout=3600)
        if len(msgs) == 0:
            raise Exception("no message")
        return msgs[0]