references #25, finished supporting all backup/restore related functions exposed in rocksdb C API.
references #25, finished supporting all backup/restore related functions exposed in rocksdb C API.

pippio/gorocksdb,venugopalkandru/gorocksdb,daaku/gorocksdb,Ingeniosity/rdb,arbortech/gorocksdb,unigraph/rdb,tecbot/gorocksdb,arbortech/gorocksdb,pippio/gorocksdb,Ingeniosity/rdb,unigraph/rdb,venugopalkandru/gorocksdb,unigraph/rdb,tecbot/gorocksdb,daaku/gorocksdb