You would be able to tell by monitoring the network tab of the browser developer tools. If post requests are being made (which they probably are, though I’m too lazy to go check) while you are typing a comment, they are most likely saving work in progress records for comments.
I heard this somewhere: “You’re in an IVF clinic. It’s on fire and you enter a burning room. On a table is a large cooler with 5 thousand fertilized eggs, and there’s also a crying, injured five-year-old girl in the room. Which one do you save? You can only save one.” The answer for most people is obviously the 5 year old and it’s not a hard choice.