Return writed

From annoying request

transport/internet/splithttp/dialer.go

@@ -495,11 +495,13 @@ func (w uploadWriter) Write(b []byte) (int, error) {
 		return 0, err
 	}
 
+	var writed int
 	for _, buff := range buffer.MultiBuffer {
 		err := w.WriteMultiBuffer(buf.MultiBuffer{buff})
 		if err != nil {
-			return 0, err
+			return writed, err
 		}
+		writed += int(buff.Len())
 	}
-	return n, nil
+	return writed, nil
 }