<PackageReference Include="System.Security.Permissions" Version="10.0.0-preview.5.25277.114" />

IsolatedStoragePermissionAttribute

Allows security actions for IsolatedStoragePermission to be applied to code using declarative security.
namespace System.Security.Permissions { public abstract class IsolatedStoragePermissionAttribute : CodeAccessSecurityAttribute { public long UserQuota { get; set; } public IsolatedStorageContainment UsageAllowed { get; set; } protected IsolatedStoragePermissionAttribute(SecurityAction action) : base(action) { } } }