Having done concurrency in Java and Rust, my experience is that Rust's concurrency primitives are an order of magnitude better than Java's. I haven't tested C#'s.
C# doesn't have Send and Sync that is true. It frequently does not need either because it uses GC instead of affine types for automatic memory management. Synchronization is indeed "just don't write bugs", where Rust offers a massive upgrade, but .NET CoreCLR's memory model is more strict than C one, like object reference assignment having release semantics, so quite a few footguns are luckily avoided: https://github.com/dotnet/runtime/blob/main/docs/design/spec...
'&' and '&mut', however, are your 'ref readonly' and 'ref' respectively.
Is there anything in C# which ensures what Rust does statically, that you must acquire a lock to access data protected by a mutex? Rust also has MutexGuard not be sendable i.e the mutex won't be released on a different thread from which it is acquired.
With traditional mutex APIs it's just far too easy to get it wrong. I think you just have to structure your thread-related APIs to be misuse resistant. As humans we're just not good enough at not making mistakes.
> I think you just have to structure your thread-related APIs to be misuse resistant
The premise of this stays. C# approaches this in a more traditional way, with exposing the set of synchronization primitives. It's a step above C and, usually, C++ still because you don't need to e.g. have an atomic reference counting for objects shared by multiple threads.
Concurrent access itself can be protected as easily as doing
lock (obj) {
// critical section
}
This, together with thread-safe containers provided by standard library (ConcurrentDictionary, ConcurrentStack, etc.) is usually more than enough.
What Rust offers in comparison is strong guarantee for complex scenarios, where you usually have to be much more hands-on. In C#, you can author types which e.g. provide "access lease", that look like 'using var scope = service.EnterScope(); ...`, where using turns into a try-finally block, where finally that calls .Dispose() on the scope is guaranteed to be executed.
It's a big topic, so if you have a specific scenario in mind - let me know.
> At the end of the day web browser is just bunch of parsers and compilers working together
At the end of the day, OS is just a bunch of command lines being piped together. /sarcasm
Sure, you are just missing: rendering, layout, security, network traffic for sockets, low-level control over hardware, writing a decent enough VM, image processing, video playback, music playback, compression, decompression, self-update, decryption, don't forget add-ons people love add-ons, also add-on security and isolation, web edit and debug tools, network analysis tools, etc.
Why would you need to reinvent networking layer instead of just sending http requests via matrue, battle tested lib available in your programming ecosystem e.g from MSFT? Same with crypto, sockets, compression, etc?
Video and audio I mentioned.
Extensions are tricky, right, but more from privacy standpoint cuz after all you can just expose too much
All the major browsers came out when Windows XP had substantial market share.
So browser vendors couldn't rely on the platform to provide up-to-date SSL support. Or MP3 support. Or MPEG-4 support. Or PDF support. This established the norm that browsers would ship their own video support, their own SSL support, and so on.
And Google realised they like the power this gives them - if Google wants to replace HTTP with QUIC or introduce a new video DRM standard, or a new video codec like VP9 - they don't need the cooperation of anyone outside of Google.
If Chrome bundles DRM support (allowing it to play Netflix), and its own HTTP/2 stack for speed - are you going to release a browser that's slower and doesn't play Netflix? Doesn't sound like a recipe for big market share.
Many of these components have been made part of the ecosystem long after they were introduced in Firefox. Also, the more platform-specific you go for each component, the more you're going to introduce subtle incompatibilities between Firefox running on different versions of Windows or in Firefox for Windows vs. macOS vs. Linux. Also, for a very, very long time, Microsoft had an extremely poor record in terms of security fixes. So what happens when you rely on a Microsoft http library and Microsoft takes a year or two to release a 0-day?
There are benefits to this approach, of course, but the costs would have been consequential.
Browsers are using new http features much earlier than they're available in the system libraries. Browsers supported http2 and 3 before they were standardised enough to include in systems. .net http client still can't even tell you about http2 early hints as far as I understand it.
It's going to be the same for crypto and compression. Systems don't ship with brotli for example. The battle tested implementations come to the browsers first in many cases - or at least they're battle tested at the point anyone starts including them in .net or Java.
> Why would you need to reinvent networking layer instead of just sending http requests via matrue, battle tested lib available in your programming ecosystem e.g from MSFT?
Because modern browsers are essentially cross-compatible OSes.