func (w *writer) Delete(cf string, key []byte) Writer {
tm := w.addWriter(cf, key)
d := cassandra.NewDeletion()
d.Timestamp = thrift.Int64Ptr(now())
tm.Deletion = d
return w
}
func (w *writer) DeleteColumns(cf string, key []byte, columns [][]byte) Writer {
tm := w.addWriter(cf, key)
d := cassandra.NewDeletion()
d.Timestamp = thrift.Int64Ptr(now())
sp := cassandra.NewSlicePredicate()
sp.ColumnNames = columns
d.Predicate = sp
tm.Deletion = d
return w
}