In HA mode, the master is down and cannot be consumed from the slave

I have met two conditions.
1. The configuration slaveReadEnable is true;
2. I didn't open the consumption of order messages.
but, still fail to consume the message of slave.

Start by reproducing the failure with slaveReadEnable set to true, order-message consumption disabled, and the master unavailable. Trace the HA slave consumption path to determine why messages are not consumed; done means ordinary messages can be consumed from the slave under those conditions.

Written by the indexing model from the issue text.