title: mypy slow when using vscode's python extension
body: <p>When enabling mypy in vscode (<code>&quot;python.linting.mypyEnabled&quot;: true,</code>),
  then any manual mypy commands become very slow and CPU intensive (10s before vs 3min after).</p>
  <p>It seems like the two mypy processes should be independent, or even aid each other through a cache, but they seem to be in each other's way.</p>
  <p>I noticed that from a clean venv it doesn't happen for a while. Only after the vscode has run mypy do the manual mypy commands become slow, even when vscode is not running anymore.</p>
  <p>The only related question I could find was <a href="https://stackoverflow.com/questions/72179618/mypy-in-vscode-consumes-too-much-memory">this</a>.</p>