PHP rate limiting client
<p>I use a variety of 3rd party web APIs, and many of them enforce rate limiting.  It would be very useful to have a fairly generic PHP library that I could rate limit my calls with.  I can think of a few ways to do it, perhaps by putting calls into a queue with a timestamp of when the call can be made, but I was hoping to avoid reinventing the wheel if someone else has already done this well.</p>
