Starting a session and closing right away does not close the JVM

[dsvensson]

Does not close all threads on shutdown, the following code has to hope for OkHttp to terminate.

val config = FileConfiguration("--conf-file=${args[0]}")
val session = Session.Builder(config).create()
session.close()

[dsvensson]

Somewhat of a workaround, shutting down OkHttp manually,

session.close()
session.client().dispatcher.cancelAll()
session.client().dispatcher.executorService.shutdownNow()

...but there's still something that causes it to hang. Needs further investigation. The above workaround makes the process exit most of the time.