Transfer cache speed test

[leonardehrenfried]

Summary

It turns out we have a pretty big blind spot in our speed tests: transfer cache computation is not measured at all. This is added in this PR.

You can see a preview of this data here: https://tinyurl.com/224xmjfe

Issue

Relates to #6357

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.81%. Comparing base (df53a35) to head (64b10c2).
Report is 1 commits behind head on dev-2.x.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             dev-2.x    #6362   +/-   ##
==========================================
  Coverage      69.81%   69.81%           
  Complexity     17939    17939           
==========================================
  Files           2042     2042           
  Lines          76645    76645           
  Branches        7830     7830           
==========================================
  Hits           53506    53506           
  Misses         20398    20398           
  Partials        2741     2741           

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