@Override
  protected void initParameter(byte[] parameter) throws InvalidProtocolBufferException {
    ReplaySyncReplicationWALParameter param =
      ReplaySyncReplicationWALParameter.parseFrom(parameter);
    this.peerId = param.getPeerId();
    param.getWalList().forEach(this.wals::add);
    this.batchSize = rs.getConfiguration().getLong(REPLAY_SYNC_REPLICATION_WAL_BATCH_SIZE,
      DEFAULT_REPLAY_SYNC_REPLICATION_WAL_BATCH_SIZE);
  }
This callable executed at RS side to replay sync replication wal.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplaySyncReplicationWALCallable.java