class HTTPClient::ProxyBasicAuth

def challenge(uri, param_str = nil)

Challenge handler: remember URL for response. 
def challenge(uri, param_str = nil)
  synchronize {
    @challenge['challenged'] = true
    true
  }
end

def get(req) 

def get(req)
  synchronize {
    return nil if !@force_auth and !@challenge['challenged']
    @cred
  }
end

def set(uri, user, passwd) 

def set(uri, user, passwd)
  synchronize do
    @cred = ["#{user}:#{passwd}"].pack('m').tr("\n", '')
  end
end