code: func (p *Pusher) BasicAuth(username, password string) *Pusher {
  	p.useBasicAuth = true
  	p.username = username
  	p.password = password
  	return p
  }
docs: // BasicAuth configures the Pusher to use HTTP Basic Authentication with the
  // provided username and password. For convenience, this method returns a
  // pointer to the Pusher itself.