Async vs Isolates | Decoding Flutter 

I was actually expecting that to happen 😂

now filip will have to re-record this video.

Great comment XD

Same thought , 😂

and then tell the first Filip (the ReceivePort) through a SendPort what the message was.

I have a sense soon there will be a demand for experienced Flutter devs.

@@RiwenX This is very true Riwen!! Soon they will required more Flutter Dev than React Dev hopefully!

I just joined yesterday, and I am enjoying flutter

Yes if flutter can handle web well. The purpose of React and flutter is for speed up development process for web and mobile. The performance is less important than speed up development. If you want performance go to its native language. In the end flutter is slightly better performance than react but react is better approach to the environment like website.

Yes! They are very similar. Two isolated processes that can only talk to each other (not mutate each others' state).

@@filiphracekHey sir, can you make a video about SendPort - ReceivePort usage inside isolates. There is not any good tutorial about it. Thank you!

@@ekremkamaz1490 Hello, He made video that You said

Same for me.

Interesting. I’ve been wondering how “lightweight” isolates are compared to something like Erlang actors or even Goroutines.

you don't really need it for that. isolates are necessary when processing big chunks of data on the device itself

There is already a video on async and another on isolates, this one is here because some people are mixing both in their heads.

This information has been out there for some time and there are good blog posts on the topic. If isolates are lightweight enough, they should probably make a bigger deal about it on their website.

I agree. Now that people are mentioning it, it's so obvious. It just didn't occur to me back when I was recording the video.

Thanks for watching, Raim! We're happy to hear you enjoyed the video 😄 You can find more Decoding Flutter episodes here: goo.gle/DecodingFlutter Happy Fluttering!

It's called the Event loop

As Shivam says: asynchronous code in Dart (and other languages) is basically an event loop, except you don't need to worry about the loop. When you get to some point where you need to wait (for human input, for example), you do `await`, which is basically like telling Dart: "continue with the event loop, and please call me again when event X is completed". You can also think of it this way: if your app is fully synchronous (no async), that's like there's only one event: program start. When that finishes, the whole program finishes as well. I'm not sure if any of this is helpful. ¯\_(ツ)_/¯

Many (most?) async tasks are blocked awaiting a response from the operating system. For example, waiting for a response to come back from a web server. In these cases, they aren’t actually doing anything and don’t load down the Dart thread at all.

@@filiphracek I think I understand how that would work for async calls that are waiting for a response. My main confusion is for async calls that are doing something like reading from a file or an image. Does an event get spun up when the async call is ready to be completed and so is processed?

@@AdrianBoyko my main confusion is about the case where they are doing something but I understand your point

I believe not. Isolates are used for large computations to complete, and only when it is complete is the result passed back to the main thread. Async, on the other hand, is the rapid movement of the main thread between the current point of execution and the point when async was encountered to check whether async method has finished doing its work. For your example, don't you think async would be appropriate to show the progress?

Unfortunately, they aren't supported at this point. In the old days, they were translated to WebWorkers, but that support was dropped a few years ago. On the web, you currently have to abstract from Isolates, and use WebWorkers yourself, or use a package that does that for you.

Aspiiire! Happy to see the size of your community on the Channel! Best wish for you! 🙏⚡️

@@filiphracek Thank you Filip for the response!

@@FlutterMapp Thanks Flutter Map 😀👋 Happy to see you again! Wish you to best too!!

@@Aspiiire Thanks! 🙌

You are right

@@marflage Thank you!

The host say "async will not create a new thread, it just runs on other parts". I can not understand this one

@@trungcaosy6178 Yes, async will not create new thread but provides us a way to write code in an asynchronous(non-blocking manner) when some tasks are executed in another thread. i.e. when the code or some heavy process is running in 'other parts'(a different thread) our main thread doesn't need to wait for the heavy process to finish executing, we can use async and tell the processor 'Hey please excuse this function it's asynchronous, the value once computed/proccessed will be available at some later point, so as of now let it return a future object'. Once the value is processed in another thread the event loop will take care of the results we get form this future which again is executed in the main thread.

thanks bro, but I think that async code will run on current thread rather than another thread because it will be handled on Event Queue as well as I/O ,gesture event. Isolate is the only thing in Flutter which can create new thread.

An isolate definitely uses another thread. But in many (most?) other languages, creating another thread doesn’t result in *isolation.* In Dart, the new thread and the original thread each have their own memory - the memory for any given thread is *isolated* from the other threads. In this respect, Dart is somewhat similar to a language like Erlang/Elixir if you think of a Dart isolate as an “actor”.

@@AdrianBoyko Thank you for the explanation.

The dart:isolate library is currently only supported by the Dart Native platform.

Oh, didn’t read the comments, and now I see I’m not the only one thinking about clones 😂

I think we all agree that this video needs to be redone with multiple Filips 🙂

I can't believe it didn't occur to me when I was recording it. I totally agree. It would also be a lot funnier. Damn.

We appreciate the positive feedback, Ehsan! You can check out even more episodes of Decoding Flutter here: goo.gle/DecodingFlutter Happy Fluttering 👍

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There are a lot of places to get help for this! Have you tried the Flutter Community Slack workspace or StackOverflow?

The difference depends on the nature of the work you're making asynchronous. The classic, most effective types of work to speed up with asynchrony are network requests or disk I/O tasks, as those effectively involve offloading the work to other parts of the computer (or other computers entirely, in the case of network requests). When you do this, your main thread "makes a mental note", as Filip described, and returns to its place when the remote work completes. Your app's performance is improved because the work intrinsically happens elsewhere, by the very nature of the work. All you have to do is make sure your main program doesn't sit and twiddle its thumbs until the remote work completes - and this is what `async-await` deliver. But what happens when the work cannot happen elsewhere? What if it has to happen on your computer, like parsing a downloaded image? In that case, using asynchrony will not help, as Dart's UI thread is still blocked up by the expensive computation. In this situation, a fresh isolate is required to recreate the scenario above of offloaded work. Once you spawn an additional isolate to parse the image, or recursively compute the 30th Fibonacci number, or whatever, you will shift your work off of the thread running your Flutter app and once again avoid dropped frames. The reason this improves your app's performance is that the new isolate physically runs on a different core in your CPU. Each core can only run one process at a time, so to truly parallelize work that is all running your machine, you must involve >1 core. In Dart, this is achieved by running some of your code on a fresh isolate. Does that help?

@@craiglabenz9147 thank you it's really good explanation i appreciate your time

@@seangreen9590 You bet!

I would say more like workers in js

Isolates are equivalent to Multiprocessing in Python as they're on a separate core and running parallel while threading in Python only runs concurrently as it uses the same threads on the same core, thus can't run two threads at the same time.

@@michaelkadziela7460 Oh! Thanks man!

This might help: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vl_AaCgudcY.html