Toit

I am building off of the `http.Server` examples, but I cannot figure out the idiomatic way to handle something like a callback. I'd like to define  a function like this:

```toit
start-server [--on-open] [--on-close] [--on-message]:
  ...
  server.listen server-socket :: | request/http.RequestIncoming writer/http.ResponseWriter |
    ...
```

But I cannot use the the passed in blocks (eg, `--on-open`) inside the lambda passed to `server.listen`. 

What is the idiomatic way to do this in Toit?

Maybe define an interface and pass the object to `start-server`?

It's not what the functional part of me wants to write, but it does seem workable.

You can use a lambda instead of a block. The `server.listen` call takes two arguments, the last one is a lambda.

So change `--on-open` to take a lambda instead, perhaps?

`start-server --on-open/Lambda --on-close/Lambda --on-message/Lambda:`

Thank you for the suggestion. I might give that a try later, but I am OK with the version I ended up with: https://github.com/anthonyjclark/cs181r/blob/main/_toit/communication/communication.toit

I did not find documentation on creating lambdas, so I took that lack of documentation as a recommendation to find a different approach.