isn't this a good place to apply Coro

No. It would completely defeat the purpose of the threading, which is to spread the cpu load of a process across multiple cores. Coro does not (can not) utilise multiple cores or processors.

The Coro docs even say

Unfortunately, the Coro docs are little more that a work of unimaginative fiction. They render some very clever code and coding--when used for appropriate purposes--almost valueless due to the asinine headline claim; knowingly, utterly biased and useless benchmark; and a complete misunderstanding or misrepresentation of ithreads.

For my purpose, they are entirely inappropriate.