Classmap not loaded?

Hi board!

I am trying to locate a custom library out of `ThirdParty/` using the classmap instead of PSR-4. 

I have been successful using the PSR-4 namespace autoloader, but as this is my auth library and will be run frequently, I want to realize the performance of the classmap feature.

Oauth class (/app/ThirdParty/Googleapi/Oauth.php):

Code:

<?php namespace ThirdParty\Googleapi;

class Oauth
{
    public function __construct()
    {

    }

    public function dance(){
        return "dance dance baby!";
    }
}

?>

Autoload.php:

Code:

$psr4 = [
       'Config'          => APPPATH . 'Config',
       APP_NAMESPACE     => APPPATH,                // For custom namespace
       'App'             => APPPATH,                // To ensure filters, etc still found,

       //'ThirdParty'      => APPPATH . 'ThirdParty'  // temporarily disable PSR to test classmap locating
        ];

    $classmap = [
       'Oauth'        => APPPATH . 'ThirdParty/Googleapi/Oauth.php'
    ];

BaseController.php

Code:

namespace App\Controllers;

use CodeIgniter\Controller;
//use ThirdParty\Googleapi\Oauth; // temporarily disable PSR to test classmap locating

class BaseController extends Controller
{

    protected $helpers = [];


    public function initController(\CodeIgniter\HTTP\RequestInterface $request, \CodeIgniter\HTTP\ResponseInterface $response, \Psr\Log\LoggerInterface $logger)
    {
        // Do Not Edit This Line
        parent::initController($request, $response, $logger);

        $this->googleapi = new Oauth();
    }

}

As this is written, I get `Error: Class 'App\Controllers\Oauth' not found` in BaseController when trying to instantiate the Oauth class. This tells me CI did not check the classmap and instead just looked for `Oauth` in the controller PSR namespace that was loaded.

Have I done something wrong or is this a bug?

Thanks!
Evan