don't fsync when finishing an asynchronous write.
don't fsync when finishing an asynchronous write.

syndicate-storage/syndicate-core,iychoi/syndicate-core,iychoi/syndicate-core,syndicate-storage/syndicate-core,iychoi/syndicate-core,iychoi/syndicate-core,syndicate-storage/syndicate-core,syndicate-storage/syndicate-core