class Net::HTTP::Persistent

def reset connection
  Thread.current[@request_key].delete connection.object_id
  Thread.current[@timeout_key].delete connection.object_id
  finish connection
  start connection
rescue Errno::ECONNREFUSED
  e = Error.new "connection refused: #{connection.address}:#{connection.port}"
  e.set_backtrace $@
  raise e
rescue Errno::EHOSTDOWN
  e = Error.new "host down: #{connection.address}:#{connection.port}"
  e.set_backtrace $@
  raise e
end