@Override
  public void appendFileInfo(final byte[] k, final byte[] v) throws IOException {
    fileInfo.append(k, v, true);
  }
Add to the file info. All added key/value pairs can be obtained using
{@link HFile.Reader#getHFileInfo()}.
@param k Key
@param v Value
@throws IOException in case the key or the value are invalid
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileWriterImpl.java