It's definitely a bit contrived, but to me it's also emblematic of the issues with async Rust.
The note on mpsc::Sender::send losing the message on drop [1] was actually added by me [2], after I wrote the Oxide RFD on cancellations [3] that this talk is a distilled form of. So even the great folks on the Tokio project hadn't documented this particular landmine.
[1] https://docs.rs/tokio/latest/tokio/sync/mpsc/struct.Sender.h...