Design and implement an API to enable RDMA as a datapath

[guhetier]

Design and review an API allowing to enable and configure the RDMA datapath.
The API must take into account the global initial configuration needed by RDMA to setup the interface.

The API could take the shape of:

• a setting at the global level and/or the connection level.

• a setting at the registration level (letting the app have one registration for RDMA, or for UDP?)

• other?

• API design

• API review

• API implementation