Concurrency error and delay in low level hook

[OliBomby]

I use your library in my application to handle various keybinds. At times people report large input delay on they keypresses while my application is open. This must be because of the low level keyboard hook being slow, which makes it quite invasive.

I managed to capture this exception in the lower level hook by accident when I was debugging my application. This looks pretty serious and such exceptions could be the cause of the occasional input delay. Due to the ephemeral nature of the bug, I can't provide good reproduction steps. I think it happened while I was typing something.

It's interesting that the modifier keys have a lock to provide exclusive access to the hash set. Why does the keys hashset not utilize a lock?

[AlexVirlan]

I think that this might be solved by using another lock on that variable. 🤔