FromILSpy.cs

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Diagnostics;
using System.Net.Http;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;

namespace Demo
{
	internal class Program
	{
		[CompilerGenerated]
		[Serializable]
		private sealed class <>c
		{
			private sealed class <<Function>b__1_3>d : IAsyncStateMachine
			{
				public int <>1__state;

				public AsyncTaskMethodBuilder<string> <>t__builder;

				[System.Runtime.CompilerServices.TupleElementNames(new string[]
				{
					"http",
					"url"
				})]
				public System.ValueTuple<HttpClient, string> httpinfo;

				public Program.<>c <>4__this;

				private string <>s__1;

				private TaskAwaiter<string> <>u__1;

				void IAsyncStateMachine.MoveNext()
				{
					int num = this.<>1__state;
					string result2;
					try
					{
						if (num != 0)
						{
						}
						try
						{
							TaskAwaiter<string> taskAwaiter;
							if (num != 0)
							{
								taskAwaiter = this.httpinfo.Item1.GetStringAsync(this.httpinfo.Item2).GetAwaiter();
								if (!taskAwaiter.IsCompleted)
								{
									this.<>1__state = 0;
									this.<>u__1 = taskAwaiter;
									Program.<>c.<<Function>b__1_3>d <<Function>b__1_3>d = this;
									this.<>t__builder.AwaitUnsafeOnCompleted<TaskAwaiter<string>, Program.<>c.<<Function>b__1_3>d>(ref taskAwaiter, ref <<Function>b__1_3>d);
									return;
								}
							}
							else
							{
								taskAwaiter = this.<>u__1;
								this.<>u__1 = default(TaskAwaiter<string>);
								this.<>1__state = -1;
							}
							string result = taskAwaiter.GetResult();
							taskAwaiter = default(TaskAwaiter<string>);
							this.<>s__1 = result;
							result2 = this.<>s__1;
						}
						catch
						{
							result2 = null;
						}
					}
					catch (Exception exception)
					{
						this.<>1__state = -2;
						this.<>t__builder.SetException(exception);
						return;
					}
					this.<>1__state = -2;
					this.<>t__builder.SetResult(result2);
				}

				[DebuggerHidden]
				void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine)
				{
				}
			}

			public static readonly Program.<>c <>9 = new Program.<>c();

			public static Func<int, int> <>9__1_1;

			[System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"http",
				"url"
			})]
			public static Func<int, System.ValueTuple<HttpClient, string>> <>9__1_2;

			[System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"http",
				"url"
			})]
			public static Func<System.ValueTuple<HttpClient, string>, Task<string>> <>9__1_3;

			public static Func<string, bool> <>9__1_4;

			public static Func<string, JObject> <>9__1_5;

			[System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"title",
				"num"
			})]
			public static Func<JObject, System.ValueTuple<string, int?>> <>9__1_6;

			[System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"title",
				"num"
			})]
			public static Action<System.ValueTuple<string, int?>> <>9__1_7;

			internal int <Function>b__1_1(int num)
			{
				return num;
			}

			[return: System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"http",
				"url"
			})]
			internal System.ValueTuple<HttpClient, string> <Function>b__1_2(int num)
			{
				return new System.ValueTuple<HttpClient, string>(new HttpClient
				{
					DefaultRequestHeaders = 
					{
						{
							"User-Agent",
							"Demo"
						}
					}
				}, string.Format("https://api.github.com/repos/Microsoft/TypeScript/issues/{0}", num));
			}

			[DebuggerStepThrough, AsyncStateMachine(typeof(Program.<>c.<<Function>b__1_3>d))]
			internal Task<string> <Function>b__1_3([System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"http",
				"url"
			})] System.ValueTuple<HttpClient, string> httpinfo)
			{
				Program.<>c.<<Function>b__1_3>d <<Function>b__1_3>d = new Program.<>c.<<Function>b__1_3>d();
				<<Function>b__1_3>d.<>4__this = this;
				<<Function>b__1_3>d.httpinfo = httpinfo;
				<<Function>b__1_3>d.<>t__builder = AsyncTaskMethodBuilder<string>.Create();
				<<Function>b__1_3>d.<>1__state = -1;
				AsyncTaskMethodBuilder<string> <>t__builder = <<Function>b__1_3>d.<>t__builder;
				<>t__builder.Start<Program.<>c.<<Function>b__1_3>d>(ref <<Function>b__1_3>d);
				return <<Function>b__1_3>d.<>t__builder.Task;
			}

			internal bool <Function>b__1_4(string html)
			{
				return !string.IsNullOrEmpty(html);
			}

			internal JObject <Function>b__1_5(string html)
			{
				return JsonConvert.DeserializeObject(html) as JObject;
			}

			[return: System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"title",
				"num"
			})]
			internal System.ValueTuple<string, int?> <Function>b__1_6(JObject jo)
			{
				string arg_4F_0;
				if (jo == null)
				{
					arg_4F_0 = null;
				}
				else
				{
					JToken expr_11 = jo["title"];
					arg_4F_0 = ((expr_11 != null) ? expr_11.Value<string>() : null);
				}
				int? arg_4F_1;
				if (jo == null)
				{
					arg_4F_1 = null;
				}
				else
				{
					JToken expr_36 = jo["num"];
					arg_4F_1 = ((expr_36 != null) ? new int?(expr_36.Value<int>()) : null);
				}
				return new System.ValueTuple<string, int?>(arg_4F_0, arg_4F_1);
			}

			internal void <Function>b__1_7([System.Runtime.CompilerServices.TupleElementNames(new string[]
			{
				"title",
				"num"
			})] System.ValueTuple<string, int?> issue)
			{
				Console.WriteLine(string.Format("[{0}] : {1}", issue.Item2, issue.Item1));
			}
		}

		private static void Main(string[] args)
		{
			Program.Function();
			Console.Read();
		}

		[DebuggerStepThrough, AsyncStateMachine(typeof(Program.<Function>d__1))]
		private static void Function()
		{
			Program.<Function>d__1 <Function>d__ = new Program.<Function>d__1();
			<Function>d__.<>t__builder = AsyncVoidMethodBuilder.Create();
			<Function>d__.<>1__state = -1;
			AsyncVoidMethodBuilder <>t__builder = <Function>d__.<>t__builder;
			<>t__builder.Start<Program.<Function>d__1>(ref <Function>d__);
		}
	}
}

Program.cs

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

namespace Demo
{
    class Program
    {
        static void Main(string[] args)
        {

            GetRandomIssues();
            Console.Read();
        }

        async static void GetRandomIssues()
        {
            var random = new Random(Environment.TickCount);
            (await Task.WhenAll(
                Enumerable
                    .Range(0, 50)
                    .Select(r => random.Next(1, 1))
                    .Distinct()
                    .OrderBy(num=>num)
                    .Select(num =>
                    {
                        var http = new HttpClient();
                        http.DefaultRequestHeaders.Add("User-Agent", "Demo");
                        return (http: http, url: $"https://api.github.com/repos/Microsoft/TypeScript/issues/{num}");
                    })
                    .Select(async httpinfo =>
                    {
                        try
                        {
                            return await httpinfo.http.GetStringAsync(httpinfo.url);
                        }
                        catch { return null; }
                    })))
                .Where(html => !string.IsNullOrEmpty(html))
                .Select(html => JsonConvert.DeserializeObject(html) as JObject)
                .Select(jo =>(title: jo?["title"]?.Value<string>(),num: jo?["num"]?.Value<int>()))
                .ToList()
                .ForEach(issue => Console.WriteLine($"[{issue.num}] : {issue.title}"));
        }
    }
}