# LibTmux::Transport::Cancellation.when-cancelled

- **Module:** LibTmux::Transport
- **Package:** LibTmux
- **Language:** Raku
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-raku/blob/0b5dd3d32e20f83a0069874e33eab0eb48f55962/lib/LibTmux/Transport.rakumod#L27
- **Page:** https://libtmux.org/en/raku/latest/reference/libtmux-transport-cancellation-when-cancelled/

```
method when-cancelled(--> Promise:D)
```

Observe cancellation through a Promise which only this token can resolve.

Observe cancellation through a Promise which only this token can resolve.