Connecting gRPC Client on Xamarin

Question

I tried to make gRPC Client work in a standard Xamarin Forms C# (for android) application. First I created a simple server to test it using Visual Studio standard services. It worked on localhost:5001. I succeeded in creating a client in C# Console Application but I could not do it in Xamarin.Forms (for Android).

LaunchSettings.json (for gRPC server)

{
  "profiles": {
    "gRPCP": {
      "commandName": "Project",
      "launchBrowser": false,
      "applicationUrl": "http://10.8.130.47:50051",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

Code that did work (in Console Application)

static GrpcChannel channel;
static MainService.MainServiceClient client;

private static async Task<string> GetFake()
{
    var reply = await clientGreeter.SayHelloAsync(new HelloRequest { Name = "OK"});
    return reply.Message;
}

private static async Task getFakeRobot()
{
    while (true)
    {
        var reply = await GetFake();
        Console.WriteLine($"Added {reply} successfully");
        await Task.Delay(1000);
    }
}

static void Main(string[] args)
{
    AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
    channel = GrpcChannel.ForAddress("http://10.8.130.47:50051");
    client = new Greeter.GreeterClient(channel);
    _ = Task.Run(() => getFakeRobot());
    while (true)
    {
        string val = Console.ReadLine();
        if (val == "break") break;
    }
}

The way I tried to connect using Xamarin

using System;
using System.Threading.Tasks;
using Grpc.Net.Client;

namespace gRPC_t
{
    public static class Control
    {
        static GrpcChannel channel;
        static Greeter.GreeterClient client;
        public static void init()
        {
            AppContext.SetSwitch(
    "System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
            channel = GrpcChannel.ForAddress("http://10.8.130.47:50051");
            client = new Greeter.GreeterClient(channel);
        }
        public static async Task<string> GetFake()
        {
            var reply = await client.SayHelloAsync(new HelloRequest { Name = "YEGOR" });
            return reply.Message;
        }
        public static async Task getFakeRobot()
        {
            while (true)
            {
                var reply = await GetFake();
                Console.WriteLine($"Added {reply} successfully");
                await Task.Delay(1000);
            }
        }
    }
}

whereas MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using gRPC_t;

namespace TEST_APP_ANDROID
{
    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            Console.WriteLine("Entry Point");
             Control.init();
            _ = Task.Run(()=>Control.getFakeRobot());
            InitializeComponent();
        }
    }
}

This way did not give me any response in Command Line (Output) I got "Entry point" message and then nothing else except the information about running threads.

Then I found another way of working with gRPC on netstandard2.0:

using System;
using System.Threading.Tasks;
using Grpc.Net.Client;
using Grpc.Core;

namespace gRPC_t
{
    public static class Control_2
    {
        static Channel channel;
        static Greeter.GreeterClient client;
        public static void init()
        {
            channel = new Channel("10.8.130.47:50051", ChannelCredentials.Insecure);
            client = new Greeter.GreeterClient(channel);
        }
        public static async Task<string> GetFake()
        {
            var reply = await client.SayHelloAsync(new HelloRequest { Name = "OK" });
            return reply.Message;
        }
        public static async Task getFakeRobot()
        {
            while (true)
            {
                var reply = await GetFake();
                Console.WriteLine($"Added {reply} successfully");
                await Task.Delay(1000);
            }
        }
    }
}

But it throws NullReferenceException (in channel = new Channel("10.8.130.47:50051", ChannelCredentials.Insecure);)

PS: I started this application on Android, connected to the same Wi-Fi with my laptop.

My IP address (by ipconfig) is

IPv4 Address. . . . . . . . . . . : 10.8.130.47
Subnet Mask . . . . . . . . . . . : 255.255.254.0
Default Gateway . . . . . . . . . : 10.8.130.1

What do I do wrong? How can I create gRPC client in Xamarin C# Android (Forms) project? The thing is I tried to create an empty project "TEST_APP_ANDROID.sln" and make simple gRPC client that operates with standard greet.proto to understand the concept of doing it.