using System;

using System.Collections.Generic;

using System.Threading.Tasks;

using System.Threading.Tasks.Dataflow;

public class Program

{

    public static async Task Main()

    {

        var actionProcessWorkplace = new ActionBlock<Workplace>((workplace) =>

        {

            Console.WriteLine("workplace name: {0}", workplace.Name);

        }, new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 2 });

        var actionProcessFacility = new ActionBlock<Facility>(async (facility) =>

        {

            Console.WriteLine("facility name: {0}", facility.Name);

            foreach (var workplace in facility.Workplaces)

                await actionProcessWorkplace.SendAsync(workplace).ConfigureAwait(false);

        }, new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 2 });

        var actionProcessCompany = new ActionBlock<Company>(async (company) =>

        {

            Console.WriteLine("company name: {0}", company.Name);

            foreach (var facility in company.Facilities)

                await actionProcessFacility.SendAsync(facility).ConfigureAwait(false);;

        }, new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 2 });

        foreach (var company in GetCompanies())

            await actionProcessCompany.SendAsync(company).ConfigureAwait(false);

        actionProcessCompany.Complete();

        await actionProcessCompany.Completion.ConfigureAwait(false);

        //actionProcessCompany.Completion.Wait();

        actionProcessFacility.Complete();

        //actionProcessFacility.Completion.Wait();

        await actionProcessFacility.Completion.ConfigureAwait(false);

        actionProcessWorkplace.Complete();

        //actionProcessFacility.Completion.Wait();

        await actionProcessWorkplace.Completion.ConfigureAwait(false);

    }

    public static List<Company> GetCompanies()

    {

        return new List<Company>

        {

            new Company

            {

                Name = "Company1",

                Facilities = new List<Facility>

                {

                    new Facility

                    {

                        Name = "Company1Facility1",

                        Workplaces = new List<Workplace>

                        {

                            new Workplace

                            {

                                Name = "Company1Facility1Workplace1"

                            },

                            new Workplace

                            {

                                Name = "Company1Facility1Workplace2"

                            }

                        }

                    }

                }

            },

            new Company

            {

                Name = "Company2",

                Facilities = new List<Facility>

                {

                    new Facility

                    {

                        Name = "Company2Facility1",

                        Workplaces = new List<Workplace>

                        {

                            new Workplace

                            {

                                Name = "Company2Facility1Workplace1"

                            },

                            new Workplace

                            {

                                Name = "Company2Facility1Workplace2"

                            }

                        }

                    }

                }

            }

        };

    }

}

​

public class Company

{

    public string Name { get; set; }

    public List<Facility> Facilities { get; set; }

}

​

public class Facility

{

    public string Name { get; set; }

    public List<Workplace> Workplaces { get; set; }

}

​

public class Workplace

{

    public string Name { get; set; }

}