Fix concurrent map writes error

[dsseng]

What does this PR do?

Fix #5953 error and prevent similar issues in accesslog in future

Motivation

Fixes #5953

More

• Added/updated tests
• Added/updated documentation

Additional Notes

[mpl]

Hi @sh7dm ,

First off, thank you for this PR.

We understand why you want to add a mutex, and that would have been my first reaction. However, we would like to avoid that as it should not be needed, because there should not be any concurrent access of the log, and we'd rather fix the origin of the issue. Also, we're concerned that adding a mutex would hide other concurrent accesses that we missed and that we would like to fix.
Which is why we did this other PR instead for now:

#5967

We're going to leave your PR open for a while, in case it turns out we still need it.

[dsseng]

okay, you're right.

[ldez]

as the user in #5953 confirm that the problem is fixed by #5967, I will close this PR.

Thank you anyway 👍