The fiber library seems to be still updated, but I can't get into the author to do a feature proposal or request a refactor. Please take a look at this: https://github.com/boostorg/fiber/issues/89 I have pinged Oliver 3 times, and also sent some emails to his git committer addresses (he uses two identities). If you (the maintainer) are aware of this issue, please respond; I'm willing to do code contributions, but I must have some opinions about that before I get on to the work.