adding rsockets support into JDK

[Chris Hegarty]

Lucy, Brian,

Argh! I didn’t realise that Lucy was not a committer on the JDK project.

> On 31 Jan 2019, at 07:27, Lu, Yingqi <yingqi.lu at intel.com> wrote:
> 
> It seems like nio-dev mailing list cannot include the attachment.
>  
> I also uploaded the same patch at http://cr.openjdk.java.net/~ylu/rsocket-branch.patch, just in case.

I integrated these changes ( that closely match Lucy's patch ):

 - rsocket-branch: Review comments from Brian, A, B, and D
  http://hg.openjdk.java.net/jdk/sandbox/rev/1e1db86ea836

- rsocket-branch: Review comment C from Brian - rename dispatcher
  http://hg.openjdk.java.net/jdk/sandbox/rev/3e1ebe33554c

 - rsocket-branch: Additional test coverage for the RDMA selector provider
  http://hg.openjdk.java.net/jdk/sandbox/rev/abd18a34acbf

-Chris.