WebSocketSessionManager ActiveIDs getter pings every client

I had a major performance issue when multiple clients are connected to my server.
I used this to send to specific clients by ID:

WebSocketServiceHost host = m_socket.WebSocketServices.Hosts.FirstOrDefault();
if (host != null)
{
    foreach (string id in host.Sessions.ActiveIDs)
    {
        if (id == myDesiredClientID)
        {
            try
            {
                host.Sessions.SendToAsync(myBase64Message, id, (bool b) => { });
            }
            catch (Exception e)
            {
                // log that something went wrong in sending
            }
        }
    }
}

After some (extensive) digging I found out that calling the getter of host.Sessions.ActiveIDs will ping every client AND wait for the answer of that ping!

Solution

I changed it to host.Sessions.IDs and it works just fine, but I don't think the getter of some list should be pinging all the clients before returning that list

Start by locating the WebSocketSessionManager implementations of ActiveIDs and IDs, then compare their getter behavior. Confirm the reported ping and wait when ActiveIDs is read; done means retrieving active client IDs no longer causes those client interactions while preserving the intended distinction from IDs.