/// <summary>Stop and remove a subscription</summary>
public async Task Remove(Subscription sub)
{
Debug.Assert(Misc.AssertMainThread());
// Stop if active
await sub.Stop();
// Remove from the active subscriptions lookup table
if (sub.ChannelId != null)
{
Active.Remove(sub.ChannelId.Value);
}
// Remove from the subs collection
Subs.Remove(sub);
sub.Api = null;
}