code: func (c *Cast) Enable(presentationUrl string) (*gcdmessage.ChromeResponse, error) {
  	var v CastEnableParams
  	v.PresentationUrl = presentationUrl
  	return c.EnableWithParams(&v)
  }
docs: // Enable - Starts observing for sinks that can be used for tab mirroring, and if set, sinks compatible with |presentationUrl| as well. When sinks are found, a |sinksUpdated| event is fired. Also starts observing for issue messages. When an issue is added or removed, an |issueUpdated| event is fired.
  // presentationUrl -