https://learn.microsoft.com/en-us/dotnet/api/system.windows.freezable.writepreamble?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-8.0
Freezable.WritePreamble Method (System.Windows) | Microsoft Learn
Verifies that the Freezable is not frozen and that it is being accessed from a valid threading context. Freezable inheritors should call this method at the...
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