nats-py broken while running opentelemetry instrumentation 0.44b0

[bvvstab]

Observed behavior

We are running nats consumers in django commands, on a kubernetes cluster with the opentelemetry operator set up.

The consumers are looking (simplified) like this:

    sub = await conn.pull_subscribe(
         ...,
        config=ConsumerConfig(
            inactive_threshold=60 * 60 * 24,
        ),
    )
    while True:
        try:
            msgs = await sub.fetch(batch=10, timeout=10)
            for msg in msgs:
                await handle_event(msg, handler)
                await msg.ack()
        except TimeoutError:
            await asyncio.sleep(10)

We use opentelemetry-operators automatic injections by adding the annotation:

annotations:
   instrumentation.opentelemetry.io/inject-python: "observability/instrumentation"

When running otel instrumentation 0.42b0 (I think), there has been no interruption, but when upgrading to 0.44b0, the consumers all fail with:

Traceback (most recent call last):
  File "/usr/local/lib/python3.12/concurrent/futures/process.py", line 263, in _process_worker
    r = call_item.fn(*call_item.args, **call_item.kwargs)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/src/lib/bvvs/events/management/commands/run_event_worker.py", line 10, in run_async_worker
    asyncio.run(run_worker())
  File "/usr/local/lib/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/asyncio/base_events.py", line 685, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/src/lib/bvvs/events/worker.py", line 75, in run_worker
    await pull_and_handle(conn)
  File "/src/lib/bvvs/events/worker.py", line 51, in pull_and_handle
    msgs = await sub.fetch(batch=10, timeout=10)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/nats/js/client.py", line 939, in fetch
    msgs = await self._fetch_n(batch, expires, timeout, heartbeat)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/nats/js/client.py", line 1093, in _fetch_n
    msg = await self._sub.next_msg(timeout=deadline)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/nats/aio/subscription.py", line 199, in next_msg
    self._pending_size -= len(msg.data)
                              ^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'data'

Expected behavior

Updating opentelemetry should not affect nats.

Server and client version

server unknown (managed at Scaleway)
nats-py 2.7.2

Host environment

No response

Steps to reproduce

No response