<PackageReference Include="System.Security.Permissions" Version="10.0.0-rc.2.25502.107" />

System.Security.Permissions.IsolatedStorageFilePermissionAttribute

public sealed class IsolatedStorageFilePermissionAttribute : IsolatedStoragePermissionAttribute
Allows security actions for IsolatedStorageFilePermission to be applied to code using declarative security. This class cannot be inherited.
public IsolatedStorageFilePermissionAttribute(SecurityAction action)

Initializes a new instance of the IsolatedStorageFilePermissionAttribute class with the specified SecurityAction.