if got zero value or invalid or nil, not pass through

main.go

@@ -1,6 +1,9 @@
 package gostream
 
-import "errors"
+import (
+	"errors"
+	"reflect"
+)
 
 type StreamOption struct {
 	WaterMark int // buffer len
@@ -124,8 +127,12 @@ func (tr *TransformStream[T, K]) OnData(cb func(K)) error {
 		go func() {
 			for k := range tr.writer {
 				transfered := tr.ITransformer.Transform(k)
+				tvalue := reflect.ValueOf(transfered)
+				if !tvalue.IsZero() && !tvalue.IsValid() {
 					tr.reader <- transfered
 				}
+
+			}
 		}()
 	}
 	return err