@Override
    public void writeInlineBlock(DataOutput out) throws IOException {
      if (singleLevelOnly) throw new UnsupportedOperationException(INLINE_BLOCKS_NOT_ALLOWED);

      // Write the inline block index to the output stream in the non-root
      // index block format.
      indexBlockEncoder.encode(curInlineChunk, false, out);

      // Save the first key of the inline block so that we can add it to the
      // parent-level index.
      firstKey = curInlineChunk.getBlockKey(0);

      // Start a new inline index block
      curInlineChunk.clear();
    }
Write out the current inline index block. Inline blocks are non-root blocks, so the non-root
index format is used.
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlockIndex.java