possible NIO selector leak in 7u25

[Bernd Eckenfels]

Hello,

we found a cause for the leak, we did not use the latest xnio-nio release.  
Looking at the NioTcpChannel code I guess that for example this commit  
could fix a potential problem (we shutdown r+w before we close, which  
would not be passed on by the older xnio-nio):

https://github.com/xnio/xnio/commit/71ebef70d11eedce9a0eb7e5de4d37ab22648b73

When we update the implementation to 3.0.8.GA we dont see the handles  
accumulate anymore. So sorry for blaming NIO (I am still not sure why this  
does not show up in the heapdumps. I have done some test programs where I  
havent closed() the channels or havent selected on the canceled keys. And  
in all those conditions I see Java heap objects representing the (open)  
FDs. But I dont see them in our test environment).

Oh well... thanks for listening, it always helps to explain your problems  
to others, especially if they are home made :)

Bernd