> There are two string types: a string that owns its contents and a string that references its contents. This is the same as in any language that uses smart pointers for resource management.

There's String, &str, Cow<?>, Rc<?> and other variants. None is canonical. I spent about 2 hours reading documentation trying to pick the right type to use and I think I ended up with Rc<Cow<String>>. But in this instance my strings represent character edits in a document. 90% of the time they're < 5 bytes long. So in 90+% of cases I should be able to avoid allocations and memory dereferencing entirely, and store the string inside the pointer. What I actually want is an efficient version of enum Str { ShortStr(char[X]), Ref(Rc<Cow<String>>) }, but encapsulated behind a common string interface. Coincidentally, this is exactly how the canonical string implementation works in obj-c and (I think) swift. Despite having 6 different options maybe the string type I actually want is buried in Cargo. I'm not sure - at this point I was tired and I stopped trying.

To me this is a classic symptom of a language trying to do too much. Having all this choice is great for systems development, but for application-level development I don't want X different string options. You want 1. And I want it to be good. Having lots of options would be fine if the language was more opinionated - "Unless you know what you're doing you should just use String, which is efficient, immutable, copy-on-write and ref counted. Click here (link to advanced section of book) to read about your other options if you want more control over allocations."

> Yes, you can. You can make a one element array and allocate and deallocate manually, just as you do in C. The offset method on pointers allows for arbitrary pointer arithmetic.

Does it? At the time even with unsafe there was no way to directly call malloc. Maybe I just couldn't find it in the docs, or maybe thats changed now. I spent weeks on and off trying to get it working, including reading the rust unsafe nomicon and writing dozens of linked list implementations. I tried out all sorts of weird ways to allocate and initialize the array. I kept thinking of new ideas, only to find out a critical piece of syntax was missing. In the end I could allocate the struct I wanted but discovered it was syntactically impossible to initialize, or something silly like that. And at that point I gave up. Maybe this problem has been fixed since. And maybe if I spent even more time trying I would have figured it out. But I was tired and I had work to do.

> I haven't used Tokio, but couldn't you use a boxed trait?

I don't know what that is. Frankly I'm still confused why Rc<> didn't work. I got about 6 different answers when I asked the rust subreddit how to fix this. Some people suggested things that also didn't compile. Some people said I should make my object 'static (no thanks). And others said the problem would be fixed when trait impl lands (whatever that is - is that what you're talking about?). This use case is literally the 'hello world' of nodejs code - attach an event handler to an object, interact with local variables each time the event fires. At least as of a year ago the tokio devs clearly thought all network servers only did request/response style interaction. All the examples on their website were either an echo server or an http server. I need streams.

I really want to be able to use rust. But so far my only experience with it has been one of frustration. It seems too immature to replace C as a systems language, and tokio seems too immature to replace Nodejs for network services. Maybe I'll revisit it in a few years, but at this point I'm more hopeful either someone will bolt decent syntax on top of Go a la coffeescript, or that Swift will add language level support for concurrency. (I'd be happy with either async or go's actor model.)