Limits user connection in pgbouncer - Mailing list pgsql-admin

How can we limit the user to  make a specific number of connections to the database?

Suppose, I have a user "user1" and I want to limit it to make only 2 connections. I have tried but not done. 

Here are my pgbouncer.ini options. 

db1 = host=localhost dbname=db1

logfile = /var/log/pgbouncer/pgbouncer.log
pidfile = /var/run/pgbouncer/pgbouncer.pid

listen_addr = *
listen_port = 6432

auth_type = md5
auth_file = /etc/pgbouncer/userlist.txt
admin_users = postgres

pool_mode = session

max_client_conn = 300

max_db_connections = 2

max_user_connections = 2

Thanks