I just published FlowBrigade.

FlowBrigade is a flow control utility library for Nim. It includes duration
parsing, retry/backoff, fallback, rate limiting, quotas, circuit breakers,
timeout/deadline helpers, bulkheads, and lock helpers.

  It is not web-specific. The goal is to make it useful for API clients, CLIs,
workers, batch jobs, and web services.

  Redis, Memcached, and Prologue adapter packages are also included separately.

  GitHub:
  https://github.com/puffball1567/flowbrigade

  Feedback, bug reports, missing test cases, and feature suggestions are very
welcome.