<PackageReference Include="NLog" Version="6.1.4" />

NLog.LayoutRenderers.Wrappers.WrapperLayoutRendererBase

public abstract class WrapperLayoutRendererBase : LayoutRenderer
Base class for LayoutRenderers which wrapping other LayoutRenderers. This has the Inner property (which is default) and can be used to wrap.
public Layout Inner { get; set; }

Gets or sets the wrapped layout. [DefaultParameter] so Inner: is not required if it's the first

protected virtual string RenderInner(LogEventInfo logEvent)

Renders the inner layout contents.

protected virtual void RenderInnerAndTransform(LogEventInfo logEvent, StringBuilder builder, int orgLength)

Appends the rendered output from Inner-layout and transforms the added output (when necessary)

protected virtual string Transform(LogEventInfo logEvent, string text)

Transforms the output of another layout.

protected abstract string Transform(string text)

Transforms the output of another layout.