code: function waitFor(state, params, callback) {
      var waiter = new AWS.ResourceWaiter(this, state);
      return waiter.wait(params, callback);
    }
docs: Waits for a given state
  
  @param state [String] the state on the service to wait for
  @param params [map] a map of parameters to pass with each request
  @option params $waiter [map] a map of configuration options for the waiter
  @option params $waiter.delay [Number] The number of seconds to wait between
  requests
  @option params $waiter.maxAttempts [Number] The maximum number of requests
  to send while waiting
  @callback callback function(err, data)
  If a callback is supplied, it is called when a response is returned
  from the service.
  @param err [Error] the error object returned from the request.
  Set to `null` if the request is successful.
  @param data [Object] the de-serialized data returned from
  the request. Set to `null` if a request error occurs.