Is it just this API, or do you struggle with other coding tasks too? From your description, you want to deeply understand the functionality to make better port

Is it just this API, or do you struggle with other coding tasks too? From your description, you want to deeply understand the functionality to make better porting, which is what I expect from a senior developer. Also, this might be a boring project, not triggering any mental reward for accomplishing it. I would focus on your learning pace for exciting topics to measure mental abilities.