GitLab

* add C++ rpc infrastructure and distributed sampler

* update

* update lint

* update lint

* update lint

* update

* update

* update

* updare

* update

* update

* update

* update serialize and unittest

* update serialize

* lint

* update

* update

* update

* update

* update

* update

* update unittest

* put Finalize() to __del__

* update unittest

* update

* delete buffer in Finalize

* update unittest

* update unittest

* update unittest

* update unittest

* update

* update

* fix small bug

* windows socket impl

* update API

* fix bug in serialize

* fix bug in serialzie

* set parent graph

* update

* update

* update

* update

* update

* update

* fix lint

* fix lint

* fix

* fix windows compilation error

* fix windows error

* change API to lower-case

* update test

* fix typo

* update

* add SamplerPool

* add SamplerPool

* update

* update test

* update

* update

* update

* update

* add example

* update

* update

* add distributed sampler demo

* add index

* update demo of distributed sampler

* fix lower-case

* print subg index

* update README.md

* update

* remove --gpu args