@Override
    protected HStore instantiateHStore(final ColumnFamilyDescriptor family, boolean warmup)
      throws IOException {
      return new BlockCompactionsInCompletionHStore(this, family, this.conf, warmup);
    }
An override of HRegion that allows us park compactions in a holding pattern and then when
appropriate for the test, allow them proceed again. This allows the compaction entry to go the
WAL before blocking, but blocks afterwards
hbase-server/src/test/java/org/apache/hadoop/hbase/TestIOFencing.java