private ReplicationSourceWALReader createNewWALReader(String walGroupId, long startPosition) {
    return replicationPeer.getPeerConfig().isSerial()
      ? new SerialReplicationSourceWALReader(fs, conf, logQueue, startPosition, walEntryFilter,
        this, walGroupId)
      : new ReplicationSourceWALReader(fs, conf, logQueue, startPosition, walEntryFilter, this,
        walGroupId);
  }
Instantiation method used by region servers
@param conf      configuration to use
@param fs        file system to use
@param manager   replication manager to ping to
@param server    the server for this region server
@param queueData the id and offsets of our replication queue
@param clusterId unique UUID for the cluster
@param metrics   metrics for replication source
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSource.java