Hi @Jack Huser,
I assume you would agree it is fair to compare apples to apples
but not horse coaches to formula-1 cars.
Being proud that I never lost a benchmark by speed I rewrote your code
that is nice to read and maintain but not very efficient, going for something
more speedy to show the limits and then checked it against your class.
My test file has only 47MB containing 181566 lines.

DEMO>write ##class(JUH.Test).ReadFile(file)
execution: 214.931024
1
DEMO>write ##class(JUH.Test).ReadQuick(file)
execution: .753696
lines: 181566
1
DEMO>write .753696/214.931024*100_" %"
.3506687801385062028 %

I think 0.35% is quite an eye catcher.

And his is the class:

 ClassMethod ReadQuick(strINReadFile As %String = "") As %Status
 {
  open strINReadFile::1 
  else  write "Missing File",! quit '$$$OK 
  set eof=##class(%SYSTEM.Process).SetZEOF(1)
  use strINReadFile
  set time1=$zh 
  for line=0:1 {
    read strBuffer if $zeof set diff=$zh-time1 quit
    // do something with strBuffer
  }
  close strINReadFile
  do ##class(%SYSTEM.Process).SetZEOF(eof)
  write !,"execution: "_diff,!,"lines: ",line,!
  quit $$$OK
 }

I just couldn't resist my nature.

I did further investigations on 'broken' input files and placed a related issue
https://github.com/MakarovS96/cache-tort-git/issues/8
It happened a little bit by accident but I found this a possible realistic scenario that explains
why the problem occurs every now and then.  You may argue this is bad handling by user.
Accepted. But not unlikely.
I found this situation:

• I have a project. with several packages and classes
• I deleted a class BUT the PACKAGE was not saved and didn't reflect the change
• From ClassMethod ExportProject(project ,1) I get this strange XML for the deleted class c:\temp\TEST\dc\MyCompany\EmployeRegister1.cls.xml <?xml version="1.0" encoding="UTF-8"?> <Export generator="IRIS" version="26"> </Export>
• now I need a GIT expert to analyze what happens with this incomplete input.
• my assumption: according to the file name there is an empty entry of type CLS named /dc/MyCompany/EmployeRegister1.cls.xml or similar
• when ist is restored it may cause the described problem togehter with the reported bug in $system.OBJ.Load() 

my pull request is posted https://github.com/MakarovS96/cache-tort-git/pull/7

When I downloaded your Repo from GitHub the docker image generated.
But I just see just NOTHING inside the container of the dc.* classes or globals that are in the repo
I couldn't find any cube or pivots or dashboards. Neither in the container nor in the repo.
Not just me, also Power BI just found NOTHING.
What do you expect me to vote for ?
Sorry.

As seen in my comment I can reproduce the error pattern and show some really dirty effects.
Someone willing to debug this source control and expose his SYSLIB may be the winner.
 

from class docs:

• property Server as %String(MAXLEN=64,MINLEN=0);

Name of the remote server where the DB resides.
If empty, the database is local.
Remote server must already be configured to be entered here.

 so this applies if you have some ECP connected DBs

BIG CONGRATULATIONS.

https://docs.intersystems.com/iris20211/csp/docbook/DocBook.UI.Page.cls?KEY=RCOS_fzdate
 

write $zd(+$h,4,,4)

s max=0,glb="^MyGlobal" f  s glb=$q(@glb) q:glb=""  s:$ql(glb)>max max=$ql(glb)
zw max

SMP > SQL 
select a table 
then Action > Tune table

Beginners see the query plan first and then create the index on items in WHERE clause.
Experts mostly reverse the sequence.

did you try 

ZN "%SYS"

   to return ? or switching to a different Namespace and back to %SYS ?

OK!  you talk about a local variable array
If you don't pass the local array with the JOB command it is not defined in the new JOB
because it is LOCAL   
except if you run  the 2 SET commands of your example also in the JOBbed routine.
also your WRITE command will fail if you don't specify some output device.
since by definition a background JOB doesn't have foreground output.

I just found Facebook link is operational again in GM.
I just had to "associate" in personal settings and it worked with no other input.
ping @Olga Zavrazhnova