Nerding a bit more, it was a bit late yesterday: this is why the Future takes this weird type called a `Pin`, which is a guarantee that the value does not move in memory while the Future is polled. This is also one of the reasons the feature took so long, Rust previously only had ways to detect potential moves in memory, but could not disallow them.
Slight word of warning: `async/await` is more than just sugar in Rust, it also enables borrowing over awaits, which was previously not possible.