better SetFillCache discussion in doc.go
better SetFillCache discussion in doc.go

DanielMorsing/rocksdb,jmhodges/levigo,jmhodges/levigo_leveldb_1.4,evanphx/levigo,chanxuehong/goleveldb,influxdata/rocksdb,elijahandrews/levigo,mikefaille/rocksdb-go,influxdata/hyperleveldb-go,influxdb/hyperleveldb-go,alberts/gorocks,influxdb/levigo,influxdb/rocksdb,dckit/rocksdb