Added a proper require 'rbconfig'
For connecting to a unix socket, use a full pathname (must begin with a slash character: '/') in place of the "host:port" pair.
If a hostname was provided that did not match the regex in `parse_hostname` then using the `res` variable would cause a NoMethodError with the message "undefined method '' for nil:NilClass". It was a bit vague so this commit will make the failure more explicit.
…n be an ActiveSupport::Duration value instead of a Fixnum.