Only load protocol if not speified

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

Author: rullzer

src/WrapperHandler.php

@@ -60,7 +60,10 @@ protected static function wrapSource($source, $context = [], $protocol = null, $
 			$class = static::class;
 		}
 
-		$protocol = self::getProtocol($class);
+		if ($protocol === null) {
+			$protocol = self::getProtocol($class);
+		}
+
 		$context = self::buildContext($protocol, $context, $source);
 		try {
 			stream_wrapper_register($protocol, $class);
@@ -106,4 +109,4 @@ protected function loadContext($name = null) {
 		}
 		return $context;
 	}
-}
+}