SeqFileIterator iterator = (SeqFileIterator) vectorIterable.iterator();
int i = 0;
while (iterator.hasNext()) {
Vector vector = iterator.next();
if (printKey) {
writer.write(iterator.key().toString());
writer.write("\t");
}
String fmtStr = useJSON ? vector.asFormatString() : VectorHelper.vectorToString(vector, dictionary);
writer.write(fmtStr);
writer.write('\n');