code: protected function autoloader($className)
      {
          $className = \ltrim($className, '\\'); // leading backslash _shouldn't_ have been passed
          if (!\strpos($className, '\\')) {
              // className is not namespaced
              return;
          }
          $psr4Map = array(
              'bdk\\Debug\\' => __DIR__,
              'bdk\\PubSub\\' => __DIR__.'/../PubSub',
              'bdk\\ErrorHandler\\' => __DIR__.'/../ErrorHandler',
          );
          foreach ($psr4Map as $namespace => $dir) {
              if (\strpos($className, $namespace) === 0) {
                  $rel = \substr($className, \strlen($namespace));
                  $rel = \str_replace('\\', '/', $rel);
                  require $dir.'/'.$rel.'.php';
                  return;
              }
          }
          $classMap = array(
              'bdk\\ErrorHandler' => __DIR__.'/../ErrorHandler/ErrorHandler.php',
          );
          if (isset($classMap[$className])) {
              require $classMap[$className];
          }
      }
docs: Debug class autoloader
  
  @param string $className classname to attempt to load
  
  @return void