Requests-Ratelimiter is a simple wrapper around pyrate-limiter that adds
convenient integration with the requests library.

Features:
- pyrate-limiter is a general-purpose rate-limiting library that implements the
  leaky bucket algorithm, supports multiple rate limits, and has optional
  persistence with SQLite and Redis backends
- requests-ratelimiter adds some conveniences for sending rate-limited HTTP
  requests with the requests library
- It can be used as either a session or a transport adapter
- It can also be used as a mixin, for compatibility with other requests-based
  libraries
- Rate limits are tracked separately per host
- Different rate limits can optionally be applied to different hosts