Windows builds time out during cache restore

Environments Windows
4

Comparing the new download logic (only on Windows by default) with the old one (used on Linux and macOS by default), I can see that the old one used to disable Nagle’s algorithm while the new one doesn’t. Might be a reason for delays.

EDIT: As found in this other post, Windows Defender is responsible for a large chunk of the slowness. Normally you’d disable it with PowerShell commands like:

Set-MpPreference -DisableArchiveScanning $true
Set-MpPreference -DisableRealtimeMonitoring $true
Set-MpPreference -DisableBehaviorMonitoring $true

… but in this case you have to execute these commands at startup, before the cache restore starts. I accomplished this by backticking the commands into environment variables:

env:
    global:
    - >
        DISABLE_WINDOWS_DEFENDER=`powershell -Command
        Set-MpPreference -DisableArchiveScanning \\\$true`
    - >
        DISABLE_WINDOWS_DEFENDER=`powershell -Command
        Set-MpPreference -DisableRealtimeMonitoring \\\$true`
    - >
        DISABLE_WINDOWS_DEFENDER=`powershell -Command
        Set-MpPreference -DisableBehaviorMonitoring \\\$true`

Now the whole build (not just the cache restore) runs much faster.

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