on migration the foreign key comes indexable how to fix this .net core ef code example

Example 1: how to add index to database code first .net core

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Blog>()
        .HasIndex(b => b.Url)
        .HasName("Index_Url");
}

Example 2: how to add index to database code first .net core

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Blog>()
        .HasIndex(b => b.Url)
        .IsUnique();
}