Add "Frequently Asked Questions" section

Author: hecrj

src/SUMMARY.md

@@ -28,3 +28,4 @@
 
 # Appendix
 - [Additional Resources](additional-resources.md)
+- [Frequently Asked Questions](faq.md)

src/faq.md

@@ -0,0 +1,62 @@
+# Frequently Asked Questions
+
+## When Will the Book Be Finished?
+Soon™. Open source is a gift; so whenever I feel like it.
+
+## How Do I Scale a Large Application?
+You split your application into multiple screens, and then use simple composition.
+
+[The Pocket Guide] has [a specific section that showcases this approach](https://docs.rs/iced/0.13.1/iced/#scaling-applications).
+
+## How Can My Application Receive Updates From a Channel? 
+You can use [`Task::run`] to generate messages from an asynchronous [`Stream`].
+
+Alternatively, if you control the creation of the channel; you can use [`Subscription::run`].
+
+[The Pocket Guide]: https://docs.rs/iced/0.13.1/iced/index.html#the-pocket-guide
+[`Task::run`]: https://docs.rs/iced/0.13.1/iced/task/struct.Task.html#method.run
+[`Subscription::run`]: https://docs.rs/iced/0.13.1/iced/struct.Subscription.html#method.run
+[`Stream`]: https://docs.rs/futures/latest/futures/stream/trait.Stream.html
+
+## Does Iced Support Right-To-Left Text and/or CJK scripts?
+Not very well yet!
+
+You may be able to render some scripts using [`Text::shaping`] with [`Shaping::Advanced`],
+but text editing for these scripts is not yet supported; and neither are [Input Method Editors].
+
+These features are in the [`ROADMAP`], however!
+
+[`Text::shaping`]: https://docs.rs/iced/0.13.1/iced/widget/text/type.Text.html#method.shaping
+[`Shaping::Advanced`]: https://docs.rs/iced/0.13.1/iced/widget/text/enum.Shaping.html#variant.Advanced
+[Input Method Editors]: https://en.wikipedia.org/wiki/Input_method
+[`ROADMAP`]: https://whimsical.com/roadmap-iced-7vhq6R35Lp3TmYH4WeYwLM
+
+## When Are the `view` and `subscription` Functions Called?
+After every batch of messages and `update` calls. But this is an implementation detail;
+and should never rely on this.
+
+Try to treat these functions as declarative, stateless functions.
+
+## Does Iced Redraw All the Time?!
+Yes! iced currently redraws after every runtime event; including tiny mouse movements.
+
+There are plans to redraw less frequently by detecting widget state changes, but performance has not
+been a priority so far.
+
+The renderers do perform quite a lot of caching; so redrawing is quite cheap. As a result,
+this is rarely an issue for most use cases!
+
+## I Am Getting A Panic Saying There Is No Reactor Running. What Is Going On?
+You are probably using `Task` to execute a `Future` that needs the `tokio` executor:
+
+```
+there is no reactor running, must be called from the context of a Tokio 1.x runtime
+```
+
+You should be able to fix this issue by enabling [the `tokio` feature flag] in the `iced` crate:
+
+```toml
+iced = { version = "0.13", features = ["tokio"] }
+```
+
+[the `tokio` feature flag]: https://docs.rs/crate/iced/latest/features#tokio