code: function install() {
  	debug( 'install()' );
  	if ( iframe ) {
  		uninstall();
  	}
  
  	buffered = [];
  
  	// listen to messages sent to `window`
  	event.bind( window, 'message', onmessage );
  
  	// create the <iframe>
  	iframe = document.createElement( 'iframe' );
  
  	// set `src` and hide the iframe
  	iframe.src = proxyOrigin + '/wp-admin/rest-proxy/?v=2.0#' + origin;
  	iframe.style.display = 'none';
  
  	// inject the <iframe> into the <body>
  	document.body.appendChild( iframe );
  }
docs: Injects the proxy <iframe> instance in the <body> of the current
  HTML page.
  
  @api private