private WALEntrySinkFilter setupWALEntrySinkFilter() throws IOException {
    Class<?> walEntryFilterClass =
      this.conf.getClass(WALEntrySinkFilter.WAL_ENTRY_FILTER_KEY, null);
    WALEntrySinkFilter filter = null;
    try {
      filter = walEntryFilterClass == null
        ? null
        : (WALEntrySinkFilter) walEntryFilterClass.getDeclaredConstructor().newInstance();
    } catch (Exception e) {
      LOG.warn("Failed to instantiate " + walEntryFilterClass);
    }
    if (filter != null) {
      filter.init(getConnection());
    }
    return filter;
  }
Create a sink for replication
@param conf conf object
@throws IOException thrown when HDFS goes bad or bad file name
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSink.java