BeatmapDecoder cannot be used in parallel #43
Description
Probably because the intermediate variable is passed through the static field instead of the parameter.
https://github.com/mrflashstudio/OsuParsers/blob/master/OsuParsers/Decoders/BeatmapDecoder.cs
https://github.com/mrflashstudio/OsuParsers/blob/master/OsuParsers/Decoders/StoryboardDecoder.cs