Add notification signaling tcp listener shutdown

The newly added signal informs all open connections that the listener
is about the close.
This is especially useful in order to shut down all connections gracefully.

Change-Id: Ie52a89d2d5671034ec62a02654351dd240302f2d

git-svn-id: https://svn.apache.org/repos/asf/etch/trunk@1679590 13f79535-47bb-0310-9956-ffa450edef68
2 files changed