private void disconnect() {
    synchronized (connLock) {
      if (this.conn != null) {
        try {
          this.conn.close();
          this.conn = null;
        } catch (IOException e) {
          LOG.warn("{} Failed to close the connection", ctx.getPeerId());
        }
      }
    }
  }
Some implementations of HBaseInterClusterReplicationEndpoint may require instantiate different
Connection implementations, or initialize it in a different way, so defining createConnection
as protected for possible overridings.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/HBaseReplicationEndpoint.java