[chore][pkg/stanza/adapter] Fix converter benchmark (#21928)

pkg/stanza/adapter/converter.go

@@ -74,15 +74,35 @@ type Converter struct {
 	logger *zap.Logger
 }
 
-func NewConverter(logger *zap.Logger) *Converter {
-	return &Converter{
+type converterOption interface {
+	apply(*Converter)
+}
+
+func withWorkerCount(workerCount int) converterOption {
+	return workerCountOption{workerCount}
+}
+
+type workerCountOption struct {
+	workerCount int
+}
+
+func (o workerCountOption) apply(c *Converter) {
+	c.workerCount = o.workerCount
+}
+
+func NewConverter(logger *zap.Logger, opts ...converterOption) *Converter {
+	c := &Converter{
 		workerChan:  make(chan []*entry.Entry),
 		workerCount: int(math.Max(1, float64(runtime.NumCPU()/4))),
 		pLogsChan:   make(chan plog.Logs),
 		stopChan:    make(chan struct{}),
 		flushChan:   make(chan plog.Logs),
 		logger:      logger,
 	}
+	for _, opt := range opts {
+		opt.apply(c)
+	}
+	return c
 }
 
 func (c *Converter) Start() {

pkg/stanza/adapter/converter_test.go

@@ -822,12 +822,11 @@ func BenchmarkConverter(b *testing.B) {
 		b.Run(fmt.Sprintf("worker_count=%d", wc), func(b *testing.B) {
 			for i := 0; i < b.N; i++ {
 
-				converter := NewConverter(zap.NewNop())
+				converter := NewConverter(zap.NewNop(), withWorkerCount(wc))
 				converter.Start()
 				defer converter.Stop()
 
 				b.ReportAllocs()
-				b.ResetTimer()
 
 				go func() {
 					for from := 0; from < entryCount; from += int(batchSize) {