title: C# System.Text.Json "rounds" doubles during serialization
body: <p>I use System.Text.Json to deserialize some stuff and then serialize it. The problem is that for example double value 99.6 is being deserialized and then serialized to 99.599999999999994.</p>
  <p>What can I do about it?</p>
  <p>Here's a reproduction in console app.</p>
  <pre><code>using System;
  using System.Text.Json;
  
  namespace ConsolePG3
  {
      class Program
      {
          static void Main(string[] args)
          {
              Person person = new Person { Value = 99.6 };
  
              var text = JsonSerializer.Serialize(person);
              Console.WriteLine(text);
              Console.ReadLine();
          }
      }
      class Person
      {
          public double Value { get; set; }
      }
  }
  </code></pre>