How to use message retransmission

[VinncentZHZ]

1.Problem found
I deployed zenoh 1.0.0~beta.1-1 on ubuntu 20.04.6. I recently in the study zenoh reliable transport (https://zenoh.io/blog/2021-06-14-zenoh-reliability/).
In this Blog, there is the following description of the message retransmission schedule:
1）Receivers control reliability by selecting a resending strategy. They declare if they need missing messages to be resent or not.
2）Senders control congestion by selecting a message dropping strategy. For each sample they decide what should be done in case of congestion (the reliability queue is full) – drop the sample or block the publication. The congestion control strategy is propagated from the sender to all involved infrastructure components and applied along the entire routing path.

According to the first point, the receiver can set the resend policy, but in zenoh 1.0.0~beta.1-1 python api declare_subscriber does not receive parameters for the resend policy（https://zenoh-python.readthedocs.io/en/1.0.0/#zenoh.Session.declare_subscriber）. This does not match the example in the Show me Some Code section of the blog post.
Here's declaration in my pub/sub example,
sub：
with zenoh.open(conf) as session:
session.declare_subscriber("test/thr/high", listener)

pub：
with zenoh.open(conf) as session:
pub1 = session.declare_publisher(
"test/thr/high",
congestion_control=zenoh.CongestionControl.BLOCK,
reliability=zenoh.Reliability.RELIABLE
)

2.Problem reproduce

1. In the publishing and receiving side set a very low bandwidth, the sender sends 1KB bytes in a row, repeat 1000 times.
2. The receiver fails to accept after receiving a portion of the message:

[Subscriber index: 125] Received SampleKind.PUT ('test/thr/high': 'Publisher index:125 ZBytes(ZBuf { slices: [[...]] })')
2024-10-24T08:03:56.522312Z DEBUG rx-0 ThreadId(07) zenoh_transport::unicast::universal::link: RX task failed: tcp/[::ffff:172.28.20.74]:45075 => tcp/[::ffff:172.28.20.47]:46578:BatchConfig { mtu: 65160, is_streamed: true, is_compression: false }: expired after 30000 milliseconds at /root/.cargo/git/checkouts/zenoh-cc237f2570fab813/f867423/io/zenoh-transport/src/unicast/universal/link.rs:263.
2024-10-24T08:03:56.522716Z DEBUG rx-0 ThreadId(07) zenoh_transport::unicast::universal::transport: [6a910ff0d467bc2ea9473aed0b5423cf] Closing transport with peer: c88bd66c4ce998afa84ac20de4819182

3.My question

1. How to configure message retransmission?
   ps: I suspect the features described in the blog post are not available in 1.0.0~beta.1-1, or maybe they need to add special compile parameters to support message retransmission.
2. How to confirm that a message has been retransmitted?
   ps: I set the message level to trace during validation. Currently, we only see a failure at the receiver, and the sender does not see any record of whether the receiver received the message.

Thanks for your attention.

[VinncentZHZ]

Before I ask the question, i assumed that the message retransmission mechanism is maintained by zenoh itself. But I've seen implementations where you can actively resume confirm in the consumption listen callback, such as:

def listener(sample: zenoh.Sample):
    print(
        f">> [Subscriber] Received {sample.kind} ('{sample.key_expr}': '{sample.payload.deserialize(str)}')"
    )

    # Send confirmation message
    sample.reply(zenoh.Confirm())

But I switch the python API documentation version to the latest, https://zenoh-python.readthedocs.io/en/latest/, is still not see "zenoh.Confirm" the interface description.
Is there anyone who has done something like this?