public boolean hasNext() throws IOException {
      HFileBlock next = iter.nextBlock();
      SeekableByteChannel channel = hFileTestRule.getRWChannel();
      if (next != null) {
        current = new HFileBlockChannelPosition(channel, next.getOffset());
      }
      return next != null;
    }
A simplified wrapper over an {@link HFileBlock.BlockIterator} that looks a lot like an
{@link java.util.Iterator}.
hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileBlockHeaderCorruption.java