@Override
    public void add(Connection connection, String poolKey) {
        ConnectionPool pool = null;
        try {
            // get or create an empty connection pool
            pool = this.getConnectionPoolAndCreateIfAbsent(poolKey, new ConnectionPoolCall());
        } catch (Exception e) {
            // should not reach here.
            logger.error(
                "[NOTIFYME] Exception occurred when getOrCreateIfAbsent an empty ConnectionPool!",
                e);
        }
        if (pool != null) {
            pool.add(connection);
        } else {
            // should not reach here.
            logger.error("[NOTIFYME] Connection pool NULL!");
        }
    }
@see com.alipay.remoting.ConnectionManager#add(com.alipay.remoting.Connection, java.lang.String)
src/main/java/com/alipay/remoting/DefaultConnectionManager.java