A collection of limiters, specialized to different use-cases, all supporting a shared subset of their interface
Resource_throttle re-implement the functionality
available in the core Async.Throttle module with the hope that these implementations
can eventually supplant that code. It is helpful to use these modules in systems that
can afford to do a bit more testing so that we can get feedback on the behavior of the
new implementation. They are intended to be mostly drop-in replacements.
nresources that are handed out in a round-robin fashion to up to