@SuppressWarnings("unchecked")
public void putNext(Tuple f) throws IOException {
if (f == null) {
return;
}
Builder builder = Protobufs.getMessageBuilder(typeRef_.getRawClass());
try {
writable.set((M) PigToProtobuf.tupleToMessage(builder, f));
writer.write(null, writable);
} catch (InterruptedException e) {
throw new IOException(e);