High CPU usage in sbt interactive mode after exiting console

[n8han]

First identified on the mailing list:
https://groups.google.com/forum/?fromgroups#!topic/dispatch-scala/CEZg9H32kX8

As far as I can tell this would have no effect on a production environment, but it's very annoying in dev.

[n8han]

First finding, if I disable daemon threads completely we fail to return to sbt interactive mode, as expected, but I am not seeing high CPU usage in that case. So it seems to have something to do with the daemon threads being killed.

[n8han]

Okay! Latest test indicates that calling nioClientSocketChannelFactory.releaseExternalResources before leaving the console avoids the issue. This is called normally by client.close(), but not if you specify your own factory -- as we have done. Also we don't want to call close().

Next step is to see if we can release automatically.

[n8han]

this is fixed by the last few commits to master