def wait_for_answer(opts = {})
      receive_trying opts
      receive_ringing opts
      receive_progress opts
      receive_answer opts
      ack_answer opts
    end
def wait_for_answer(opts = {})
      receive_trying opts
      receive_ringing opts
      receive_progress opts
      receive_answer opts
      ack_answer opts
    end
Convenience method to wait for an answer from the called party

 This sets expectations for optional SIP 100, 180 and 183,
 followed by a required 200 and sending the acknowledgement.

 @param [Hash] opts A set of options to modify the expectations