src/StoragePluginManager.php
public function validatePlugin($plugin) {
        if ($plugin instanceof Storage\StorageInterface) {
            return;
        }

        throw new Storage\Exception\RuntimeException(sprintf('Plugin of type %s is invalid; must implement %s\Storage\StorageInterfaceInterface', (is_object($plugin) ? get_class($plugin) : gettype($plugin)), __NAMESPACE__));
    }
public function validatePlugin($plugin) {
        if ($plugin instanceof Storage\StorageInterface) {
            return;
        }

        throw new Storage\Exception\RuntimeException(sprintf('Plugin of type %s is invalid; must implement %s\Storage\StorageInterfaceInterface', (is_object($plugin) ? get_class($plugin) : gettype($plugin)), __NAMESPACE__));
    }
Validate the plugin

Checks that the adapter loaded is an instance
of Storage\StorageInterfaceInterface.

@param  mixed $plugin
@return void
@throws Exception\RuntimeException if invalid