title: After Process.wait, $?.exited? is false
body: <p>If I run the following:</p>
  
  <pre><code>Process.kill "KILL", pid
  Process.wait pid
  raise "application did not exit" if not $?.exited?
  raise "application failed" if not $?.success?
  </code></pre>
  
  <p>I get the error "application did not exit". Why is <code>Process.wait</code> not waiting? More precisely, why does <code>Process.wait</code> set <code>$?</code> to a not-exited status?</p>