HardcopyFormatPluginManager3.php

<?php

class HardcopyFormatPluginManager extends DefaultPluginManager {

  protected $config;

  public function __construct(\Traversable $namespaces, ConfigFactory $config) {
    $this->config = $config;
    parent::__construct('Plugin/HardcopyFormat', $namespaces, 'Drupal\hardcopy\Annotation\HardcopyFormat');
  }

  public function createInstance($plugin_id, array $configuration = array()) {
    $configuration += (array) $this->config->get('hardcopy.format')->get($plugin_id);
    return parent::createInstance($plugin_id, $configuration);
  }
}