Auth and ACL Auth Api timeouts

[YashJainSC]

We are noticing intermittent spikes in timeout errors

logs:

ClientIp@ip:ports [Auth http] Request auth path: /service/v1/emqx/auth, error: timeout

Also noticing this logs whenever timeouts error occure

ehttpc: Received 'gun_error' message from unknown stream ref

I am not sure whether this is due to connection timeout or request timeout, how to figure that out ?

Anything we can do here, currently we are using default settings, will increasing pool size help ? currently for auth + acl auth APIs we have about ~4000 requests per second

[YashJainSC]

emqx/emqx#8566