PortablePrism.Portable by Andrii Chebukin

<PackageReference Include="PortablePrism.Portable" Version="1.0.1" />

 DataEventArgs<TData>

public class DataEventArgs<TData> : EventArgs
Generic arguments class to pass to event handlers that need to receive data.
public TData Value { get; }

Gets the information related to the event.

public DataEventArgs(TData value)

Initializes the DataEventArgs class.