esp8266httpupdateserver progress bar (of sorts)?

[cmdrscotty]

(apologies if this isn't the right place to ask this).

With the esp8266HTTPUpdateServer.h library, I see that it does have steps to write to Serial when it's updating, and I can see where in the code it runs instructions to loop until it's done updating (writes '.' to Serial until it's done updating).

I'm coming up short on how to get that to update a variable in my sketch so that I can act upon that (like increment a progress bar or display).

edit: for clarification, it's more specifcially in ESP8266HTTPupdateServer-impl.h around line 115:

     } else if(_authenticated && upload.status == UPLOAD_FILE_WRITE && !_updaterError.length()){
        if (_serial_output) Serial.printf(".");
        

    it loops this section over and over while the update is happening until it's completed.