How to determine if my iPhone XS is Fast Charging?

I recently got myself a USB Type C to Lighting Cable and a 30W USB Type C Adaptor(USB-PD). When I plug in the charger to my iPhone, I find my phone charging noticeably faster than normal but there doesn't seem to be any indication on the screen regarding the device being Fast Charged.

I read online about a "Double Ding" sounds when plugging in, but I don't think it seems to happen for my device.

I have a iPhone XS Max running latest version of iOS 12.

There’s no on-screen indication of the charging speed on current iOS versions.

The only way to really know is to time the charging, or use external hardware for USB-PD debugging that can show you the actual watts.