BinaryFormatter in netstandard 1.5
<p>According to the <a href="https://github.com/dotnet/corefx/blob/master/Documentation/architecture/net-platform-standard.md" rel="noreferrer">List of .NET CoreFx APIs and their associated .NET Platform Standard version</a>, System.Runtime.Serialization.Formatters is added into to the .NET Platform Standard since 1.3, which is cool, but when I try to create a .Net Core class library targeting netstandard1.5 under.Net Core RC2, I can't use it.</p>

<p>The code is simple, just intending to declare a BinaryFormatter:</p>

<pre><code>public class Problems {
    private System.Runtime.Serialization.Formatters.Binary.BinaryFormatter _formatter;
}
</code></pre>

<p>Error is :</p>

<blockquote>
  <p>Error CS0234 The type or namespace name 'Serialization' does not exist
  in the namespace 'System.Runtime' (are you missing an assembly
  reference?)</p>
</blockquote>

<p>Here is the project.json, which I did no modifications:</p>

<pre><code>{
  "version": "1.0.0-*",

  "dependencies": {
    "NETStandard.Library": "1.5.0-rc2-24027",
  },

  "frameworks": {
    "netstandard1.5": {
      "imports": "dnxcore50"
    }
  }
}
</code></pre>

<p>So, is there another package that I need depend on? And Why? Shouldn't a netstandard moniker be enough for all the APIs in the list?</p>