class HTTPClient::NegotiateAuth

def challenge(uri, param_str)

Challenge handler: remember URL and challenge token for response. 
def challenge(uri, param_str)
  synchronize {
    if param_str.nil? or @challenge[uri].nil?
      c = @challenge[uri] = {}
      c[:state] = :init
      c[:authphrase] = ""
    else
      c = @challenge[uri]
      c[:state] = :response
      c[:authphrase] = param_str
    end
    true
  }
end