fix(parallel-transform): return a class instead of an instance in .create

Author: Caerostris

src/parallel-transform.js

@@ -53,7 +53,7 @@ export default class ParallelTransform extends stream.Transform {
       _parallelTransform = transformFunction;
     }
 
-    return new Transform();
+    return Transform;
   }
 
   /**

test/parallel-transform.js

@@ -72,9 +72,9 @@ test.cb('should pass options on to the stream.Transform constructor', t => {
 });
 
 test('should allow instantiation via function call', t => {
-  const stream = ParallelTransform.create(1, (data, encoding, done) => {
+  const PStream = ParallelTransform.create(1, (data, encoding, done) => {
     done(null, data);
   });
 
-  t.true(stream instanceof ParallelTransform);
+  t.true(new PStream() instanceof ParallelTransform);
 });