Need reviewer for 6913877: (fs) AsynchronousFileChannel.write can return wrong result under load [win]

[Alan Bateman]

This one is a Windows specific reliability issue with 
AsynchronousFileChannel.write. It's the issue that Joel Buckley brought 
up on nio-discuss a few days ago. Under load conditions (duplicates for 
me intermittently on a 8-core server) it is possible for 
AsynchronousFileChannel.write (or read) to complete with the incorrect 
result. The issue is similar to 6834246 in that the implementation is 
using the number of bytes transferred, as returned by 
WriteFile/ReadFile, as the result. This result is only reliable for 
synchronous operations so this patch changes the implementation so that 
result is always handled via the completion notification. The webrev is 
here:
  http://cr.openjdk.java.net/~alanb/6913877/webrev.00/

Thanks,
Alan.