Don't use async in server code when it's more trouble than it's worth

[DartBot]

This issue was originally filed by jjinux...@google.com

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In one of Seth Ladd's slides, he has this:

main() {
  File script = new File(new Options().script);
  script.directory().then((Directory d) {
    runServer(d.path);
  });
}

This requires an asynchronous callback to get d.path. As far as I know, UNIX doesn't actually have an asynchronous file API, so this must be using a thread under the covers. Using a thread in order to provide an asynchronous API with a callback makes both the implementation and the API a lot more complicated, and I don't think there's much benefit in this case.

[madsager]

You can always use script.directorySync() if you feel like it. The slide is correct as is. I'll let Seth decide if he wants to do anything about this. :-)

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cc @sethladd.
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[sethladd]

Good point. I'll leave for now, because that's what I showed on stage. But in future I'll use sync methods where appropriate.

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Removed Type-Defect label.
Added Type-Enhancement, WontFix labels.

[DartBot]

This comment was originally written by jjinux...@google.com

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Removed Area-Site label.
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[kevmoo]

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