Flaky test on windows / python 3.9

```
________ test_send_remote_failover_sync_non_transport_exception_error _________

should_try =
caplog = <_pytest.logging.LogCaptureFixture object at 0x0000019D45CCBE80>

@mock.patch("elasticapm.transport.base.TransportState.should_try", return_value=True)
def test_send_remote_failover_sync_non_transport_exception_error(should_try, caplog):
client = Client(
server_url="http://example.com/",
service_name="app_name",
secret_token="secret",
transport_class="tests.fixtures.MockSendHTTPTransport",
metrics_interval="0ms",
metrics_sets=[],
)

# test error
client._transport.send_mock.side_effect = ValueError("oopsie")
with caplog.at_level("ERROR", "elasticapm.transport"):
client.capture_message("foo", handled=False)
try:
client._transport.flush()
except ValueError:
# give flush a bit more room because we may take a bit more than the max timeout to flush
client._transport._flushed.wait(timeout=1)
> assert client._transport.state.did_fail()
E assert False
E + where False = >()
E + where > = .did_fail
E + where = .state
E + where = ._transport

tests\client\client_tests.py:297: AssertionError
---------------------------- Captured stderr call -----------------------------
{"@timestamp":"2025-12-16T02:38:16.408Z","log.level":"warning","message":"Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ReadTimeoutError(\"HTTPConnectionPool(host='example.com', port=80): Read timed out. (read timeout=5)\")': /","ecs.version":"1.6.0","log":{"logger":"urllib3.connectionpool","origin":{"file":{"line":868,"name":"connectionpool.py"},"function":"urlopen"},"original":"Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ReadTimeoutError(\"HTTPConnectionPool(host='example.com', port=80): Read timed out. (read timeout=5)\")': /"},"process":{"name":"MainProcess","pid":3960,"thread":{"id":6368,"name":"eapm event processor thread"}},"service":{"name":"app_name"}}
Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ReadTimeoutError("HTTPConnectionPool(host='example.com', port=80): Read timed out. (read timeout=5)")': /
```

Comienza con test_send_remote_failover_sync_non_transport_exception_error en tests/client/client_tests.py e inspecciona el estado del transporte y el momento del flush alrededor de la aserción que falla. Reproduce la prueba en Windows con Python 3.9 y, después, verifica que la prueba observe de forma fiable el estado fallido esperado sin introducir flakiness específica de la plataforma.

Escrito por el modelo de indexación a partir del texto del issue.