public synchronized void resetBuffer() {
      readRowsIndexInBuffer = 0;
      recordsNumInValBuffer = 0;
    }
Resets the values which determine if there are more rows in the buffer

This can be used after one calls seek or sync, if one called next before that.
Otherwise, the seek or sync will have no effect, it will continue to get rows from the
buffer built up from the call to next.
ql/src/java/org/apache/hadoop/hive/ql/io/RCFile.java