Why does HMACStrategy.Generate uses a lock?

[mitar]

Preflight checklist

• [X] I could not find a solution in the existing issues, docs, nor discussions.
• [X] I agree to follow this project's Code of Conduct.
• [X] I have read and am following this repository's Contribution Guidelines.
• [ ] I have joined the Ory Community Slack.
• [ ] I am signed up to the Ory Security Patch Newsletter.

Ory Network Project

No response

Describe the bug

While reading the code, I noticed that HMACStrategy.Generate uses a mutex lock, but I do not get why it exists. No code there has any global or local state?

This was introduced in https://github.com/ory/fosite/commit/b4b9be5640c9d814b35f54b2c8621137364209ca, but I also do not get why.

Given that this is used a lot, I think mutex could be removed?

Reproducing the bug

N/A

Relevant log output

No response

Relevant configuration

No response

Version

latest master

On which operating system are you observing this issue?

None

In which environment are you deploying?

None

Additional Context

No response