Connection requests from multiple clients

[rrgargeya]

In the ucp_client_server.c example, there is this comment

/* Server is always up listening /
while (1) {
/ Wait for the server to receive a connection request from the client.
* If there are multiple clients for which the server's connection request
* callback is invoked, i.e. several clients are trying to connect in
* parallel, the server will handle only the first one and reject the rest */

For the rejected client connections, how can the clients recognize their connection requests were rejected by the server, and how can they retry? The goal is for all the clients to successfully connect to the server.