Clarify the current semantics of flush().
Clarify the current semantics of flush().

No code change, just javadoc.

adityakishore/asynchbase,adityakishore/asynchbase,tsuna/asynchbase,yuzhu712/asynchbase,OpenTSDB/asynchbase,OpenTSDB/asyncbigtable,tsuna/asynchbase,SteamShon/asynchbase,yuzhu712/asynchbase,mapr/asynchbase,nvoron23/asynchbase,manolama/asynchbase,pythian/asynchbase,hhshuai/asynchbase,manolama/asyncbigtable,Connexity/asynchbase,mway08/asynchbase,angushe/asynchbase,OpenTSDB/asynchbase,angushe/asynchbase,SteamShon/asynchbase,manolama/asynchbase,hzy001/asynchbase,Connexity/asynchbase,hhshuai/asynchbase,StumbleUponArchive/asynchbase,tempbottle/asynchbase,hzy001/asynchbase,nvoron23/asynchbase,StumbleUponArchive/asynchbase,mway08/asynchbase,tempbottle/asynchbase,mapr/asynchbase