Release Note: Allow use of TransmitFile on Microsoft Windows

Applications running on server editions of Microsoft Windows that make heavy use of `java.nio.channels.FileChannel.transferTo` may see performance improvements if the implementation uses `TransmitFile`. `TransmitFile` makes use of the Windows cache manager to provide high-performance file data transfer over sockets. The system property "`jdk.nio.enableFastFileTransfer`" controls whether the JDK uses `TransmitFile` on Microsoft Windows. It is disabled by default but can be enabled by setting the system property on the command line with `-Djdk.nio.enableFastFileTransfer` or `-Djdk.nio.enableFastFileTransfer=true`.