steps

1. Addsite-sbt to a project.
2. RunpreviewAuto.
3. Press any key.

Reproduction here:https://github.com/steinybot/bug-reports/tree/sbt/terminal-is-available

problem

It does not stop.

expectation

It should stop.

notes

sbt/sbt-site#168

unfiltered.util.RunnableServer has a busy loop polling forSystem.in.available() to be > 0 but it never is. This is becausesbt.internal.util.Terminal.proxyInputStream does not overrideavailable but it should.