Why do you not use another queue for library?

[AlexIzh]

You have serialQueue in the your code and method addRequestToQueue. But serialQueue isn't used anywhere and method addRequestToQueue calls closure in the current queue and doesn't use serialQueue. Why? I have a lot of issues because it. Did you do it because some special issue or not? If not, I can create pull request with this

[flightonary]

Oh... sorrry. this is my stupid mistake.
I corrected this issue.