C# Online Compiler | .NET Fiddle

// Entity Framework Extensions
// Doc: https://entityframework-extensions.net/bulk-savechanges

// @nuget: Z.EntityFramework.Extensions
// @nuget: EntityFramework

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Data.Entity;
using System.Linq;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

public class Program
{
	public static void Main()
	{		
		Z.EntityFramework.Extensions.EntityFrameworkManager.PreBulkSaveChanges = context => {			
			if(context.Database.Connection.State != System.Data.ConnectionState.Open)
			{
					context.Database.Connection.Open();
			}
			
			using (var command = context.Database.Connection.CreateCommand())
			{
				command.CommandText = "EXEC sp_set_session_context 'Customer_id', 3; ";
				command.ExecuteNonQuery();
			}
		};

		using (var context = new EntityContext())
		{			
			context.Customers.Add(new Customer() { Code = "Customer_A"});	

			context.BulkSaveChanges();
				
			FiddleHelper.WriteTable(context.Customers.AsNoTracking().ToList());
		}
	}
	
	public class EntityContext : DbContext
	{
		public EntityContext() : base(FiddleHelper.GetConnectionStringSqlServer())
		{

		}
		
		public DbSet<Customer> Customers { get; set; }
		
		protected override void OnModelCreating(DbModelBuilder modelBuilder)
		{
		}
	}
	
	public class Customer
	{
		[Key]
		[DatabaseGenerated(DatabaseGeneratedOption.None)]
		public int CustomerID { get; set; }
		public string Code { get; set; }
	} 
}

 
// Entity Framework Extensions
// Doc: https://entityframework-extensions.net/bulk-savechanges
​
// @nuget: Z.EntityFramework.Extensions
// @nuget: EntityFramework
​
using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Data.Entity;
using System.Linq;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
​
public class Program
{
    public static void Main()
    {       
        Z.EntityFramework.Extensions.EntityFrameworkManager.PreBulkSaveChanges = context => {           
            if(context.Database.Connection.State != System.Data.ConnectionState.Open)
            {
                    context.Database.Connection.Open();
            }
            

Cached Result

InvoiceID	Description
1	Invoice_A
2	Invoice_B

InvoiceItemID	Description
1	Invoice_B_InvoiceItem_A
2	Invoice_B_InvoiceItem_B
3	Invoice_A_InvoiceItem_A
4	Invoice_A_InvoiceItem_B