@Override
  public boolean hasNext() {
    updateCurrentIterator();
    return currentIterator.hasNext();
  }
(startingFileOffset, startingRecordOffset) points to the next row that the reader should resume
from. E.g., if the seek position is (file=0, record=1), seek moves the iterator position to the
second row in file 0. When next() is called after seek; the second row from file 0 should be
returned.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/read/source/DataIterator.java