Remove runSync since it speeds-up ~30%

pipeline_benchmark_test.go

@@ -400,12 +400,12 @@ func BenchmarkPipeline_Run(b *testing.B) {
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
+		b.StartTimer()
 		err := pipe.Run(graph, ctx)
-
 		b.StopTimer()
+
 		if err != nil {
 			b.Fail()
 		}
-		b.StartTimer()
 	}
 }

run.go

@@ -47,15 +47,3 @@ func spawnAsync(workers int, run func(index int) error) error {
 	wg.Wait()
 	return errResult.Get()
 }
-
-// Run synchronously a number of workers. If one of them fails, the operation is aborted and the error returned.
-func runSync(workers int, run func(index int) error) error {
-	for i := 0; i < workers; i++ {
-		err := run(i)
-
-		if err != nil {
-			return err
-		}
-	}
-	return nil
-}

sequential_group.go

@@ -3,9 +3,14 @@ package pipeline
 type sequentialGroup []Stage
 
 func (s sequentialGroup) Run(executor Executor, ctx Context) error {
-	return runSync(len(s), func(index int) error {
-		return s[index].Run(executor, ctx)
-	})
+	for _, stage := range s {
+		err := stage.Run(executor, ctx)
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func (s sequentialGroup) Draw(graph GraphDiagram) {

sequential_stage.go

@@ -3,9 +3,14 @@ package pipeline
 type sequentialStage []Step
 
 func (s sequentialStage) Run(executor Executor, ctx Context) error {
-	return runSync(len(s), func(index int) error {
-		return executor.Run(s[index], ctx)
-	})
+	for _, step := range s {
+		err := executor.Run(step, ctx)
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func (s sequentialStage) Draw(graph GraphDiagram) {