fix: Avoid invalid memory access in the logger

[Swatinem]

This also turns on the logger for the HTTP-based tests.

Fixes #309

[daxpedda]

Just tried it, works perfectly 👌.

[jan-auer]

Thanks for the fix! This originated in my comment at #301 (comment), which was written from poor memory about the API without testing it myself.

Are there still tests running without logs? We need to ensure that both paths are properly tested.

Please separate out all unrelated changes to tests into a separate PR, and then let's get this released as 0.3.4 directly on top of 0.3.3. We'll not merge any further features until code coverage is in place, and we run all tests with memory/address sanitizers.

[Swatinem]

Are there still tests running without logs? We need to ensure that both paths are properly tested.

we test both with the standard http transport, with logs, and we also test with a specific stdout transport without logs, since I think that interferes with the way we capture the output, although stderr should be separate.