"Under the Hood" chapter doesn't have any `block_on`

[beauxq]

After reading chapter 1, I was wondering what block_on was doing under the hood.

• What happens if I call block_on in 2 different threads?
• Do they both go to the same event loop?
• Or does it make a new event loop every time I call block_on?
• What happens if I call block_on inside an async function?

Then I saw the title of chapter 2 and I thought "That's perfect - just what I wanted!"

Except it wasn't what I wanted. Chapter 2 didn't have any block_on.