title: IndexAnnotation to EF Core
body: <p>I have this code in EF 6.2 </p>
  
  <pre><code>public class ClientNotificationMap : EntityTypeConfiguration&lt;ClientNotification&gt;
  {
      public ClientNotificationMap()
      {
          HasKey(x =&gt; x.RelationalId);
  
          Property(x =&gt; x.SubscriptionId)
              .IsRequired()
              .HasMaxLength(400)
              .HasColumnAnnotation(IndexAnnotation.AnnotationName, new  IndexAnnotation(new IndexAttribute()));
       }
  }
  </code></pre>
  
  <p>which I want to migrate to Core 2.2</p>
  
  <pre><code>public class ClientNotificationMap : IEntityTypeConfiguration&lt;ClientNotification&gt;
  {
      public ClientNotificationMap()
      {
  
      }
  
      public void Configure(EntityTypeBuilder&lt;ClientNotification&gt; builder)
      {
          builder.HasKey(x =&gt; x.RelationalId);
  
          builder.Property(x =&gt; x.SubscriptionId)
              .IsRequired()
              .HasMaxLength(400)
              .HasColumnAnnotation(IndexAnnotation.AnnotationName, new IndexAnnotation(new IndexAttribute()));
      }
  }
  </code></pre>
  
  <p>Does anyone know how to change the</p>
  
  <pre><code>                .HasColumnAnnotation(IndexAnnotation.AnnotationName, new IndexAnnotation(new IndexAttribute()));
  </code></pre>
  
  <p>In Core it doesn't seem to be supported. Also I don't find anything relative to the web.</p>