Non-tokio executor & timeouts

When using an executor that is different from tokio (in my case glib), launching a request from the client results in the following message at runtime:
```
050, marker: }), cache: ThreadCache { is_unread: true, has_attachment: false, tags: [] } }))
INFO inox_gtk::components::thread_view > load_thread: Thread { thread: Some(Thread { ptr: 0x55a29e2a0050, marker: }), cache: ThreadCache { is_unread: true, has_attachment: false, tags: [] } }
thread 'main' panicked at 'there is no timer running, must be called from the context of Tokio runtime', /home/dirk/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.2.13/src/time/driver/handle.rs:24:9
stack backtrace:
```

It seems tokio timeouts are not compatible with other runtimes. It'd be cool if there was a runtime-agnostic solution. Peraps https://github.com/async-rs/futures-timer ?