Sometimes, when downloading information for large numbers of KOs from the KEGG API, the API will forbid downloads because there are too many requests (see this [issue](https://github.com/lozuponelab/AMON/issues/9#issuecomment-601871461) in AMON). This isn't an ideal fix, but with these updates, if the asynchronous requests are forbidden, the KOs will be downloaded sequentially instead of asynchronously. This is quite a bit slower, but it gets around the issue.
The request rate limit of the API isn't clearly laid out, so this is what we have for now. Perhaps a future approach should have some batch size limit for asynchronous requests.