https://learn.microsoft.com/es-es/dotnet/api/microsoft.visualc.stlclr.unarydelegate-2?view=netframework-4.8.1
UnaryDelegateTArg,TResult Delegate (Microsoft.VisualC.StlClr) | Microsoft Learn
Describes a one-argument delegate. You use it to specify the argument and return type of the delegate.
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