@Override
    public synchronized boolean isIdle() {
        return mainChannel.isOpen() && !mainChannel.isActive();
    }
Determines if this instance is currently in a state where it is actively serving connections or not.
Channel must be open with no connections if it is idle

@return false when this instance is started and is currently being used to serve connections (otherwise true)
xmppserver/src/main/java/org/jivesoftware/openfire/spi/NettyConnectionAcceptor.java