use `Mutex` instead of `RwLock` for securing the inner data

[hozan23]

This addresses the issue #42

The use of RwLock is typically used when there is a need for multiple readers and infrequent writers, as RwLock allows multiple concurrent readers or a single writer. However, most functions were using the write() method, while the read() method was rarely used.

[hozan23]

@zeenix thanks, I updated the commit message.

[fogti]

do we have some benchmarks to check that this doesn't cause sigificant performance regressions?

[zeenix]

do we have some benchmarks to check that this doesn't cause sigificant performance regressions?

No but is there a reason we'd suspect so? 🤔

[hozan23]

@fogti In theory, it should not cause any performance regressions. #42 didn't mention any performance issues with using rwlock, but as far as I know, the only issue with rwlock is writer starvation, whereas a mutex cannot have this issue. However, I agree that we do need some benchmarks to check the performance. I will do it when I have time.

[fogti]

@hozan23 tbh, the link to the introduction of rwlock suffices for me.