[MM-54288] Support Packet V2 (#29403)

server/public/utils/timeutils/time.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package timeutils
+
+import (
+	"time"
+)
+
+const (
+	RFC3339Milli = "2006-01-02T15:04:05.999Z07:00"
+)
+
+func FormatMillis(millis int64) string {
+	return time.UnixMilli(millis).Format(RFC3339Milli)
+}
+
+func ParseFormatedMillis(s string) (millis int64, err error) {
+	if s == "" {
+		return 0, nil
+	}
+
+	t, err := time.Parse(RFC3339Milli, s)
+	if err != nil {
+		return 0, err
+	}
+
+	return t.UnixMilli(), nil
+}