timestamping: clarify potential multi-threading issues
timestamping: clarify potential multi-threading issues

scholzd/MoonGen,gallenmu/MoonGen,emmericp/MoonGen,duk3luk3/MoonGen,NetronomeMoongen/MoonGen,gallenmu/MoonGen,gallenmu/MoonGen,duk3luk3/MoonGen,dschoeffm/MoonGen,bmichalo/MoonGen,scholzd/MoonGen,NetronomeMoongen/MoonGen,dschoeffm/MoonGen,bmichalo/MoonGen,atheurer/MoonGen,gallenmu/MoonGen,NetronomeMoongen/MoonGen,dschoeffm/MoonGen,scholzd/MoonGen,gallenmu/MoonGen,emmericp/MoonGen,emmericp/MoonGen,gallenmu/MoonGen,gallenmu/MoonGen,atheurer/MoonGen,duk3luk3/MoonGen,gallenmu/MoonGen,bmichalo/MoonGen,bmichalo/MoonGen,atheurer/MoonGen