private void useDifferentDFSClient() throws IOException {
    // make fs act as a different client now
    // initialize will create a new DFSClient with a new client ID
    fs.initialize(fs.getUri(), conf);
  }
Test old recovered edits file doesn't break WALSplitter. This is useful in upgrading old
instances.
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALSplit.java