Set span status to codes.Error.

fcm.go

@@ -463,17 +463,29 @@ func (c *Client) doSendEachInBatch(
 	// Wait for all Validate/Send calls to finish
 	wg.Wait()
 
-	successCount := 0
+	successAmount := 0
 	for _, r := range responses {
 		if r.Success {
-			successCount++
+			successAmount++
 		}
 	}
 
+	failedAmount := len(responses) - successAmount
+
+	span.SetAttributes(
+		attribute.Int("res.total", len(responses)),
+		attribute.Int("res.sent", successAmount),
+		attribute.Int("res.failed", failedAmount),
+	)
+
+	if failedAmount > 0 {
+		span.SetStatus(codes.Error, "Got errors from method Client.Send().")
+	}
+
 	return MessageMultiSendResponse{
 		Responses: responses,
-		Sent:      successCount,
+		Sent:      successAmount,
-		Failed:    len(responses) - successCount,
+		Failed:    failedAmount,
 	}, nil
 }