Manages persistent connections using Net::HTTP plus a speed fix for Ruby 1.8.
It's thread-safe too!
Using persistent HTTP connections can dramatically increase the speed of HTTP.
Creating a new HTTP connection for every request involves an extra TCP
round-trip and causes TCP congestion avoidance negotiation to start over.
Net::HTTP supports persistent connections with some API methods but does not
handle reconnection gracefully. Net::HTTP::Persistent supports reconnection
and retry according to RFC 2616.