title: How to use the Microsoft.Bcl.Async right?
body: <p>I use the <code>Microsoft.Bcl.Async</code> <a href="https://nuget.org/packages/Microsoft.Bcl.Async/">package</a> in a project and this project is a referenced by another project that does not use async features.</p>
  
  <p>Now I get this error warning when I compile the solution (or only the second project):</p>
  
  <blockquote>
    <p>The primary reference "XYZ.dll" could not be resolved because it has an indirect dependency on the framework assembly "System.Runtime, Version=1.5.11.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0". To resolve this problem, either remove the reference "XYZ.dll" or retarget your application to a framework version which contains "System.Runtime, Version=1.5.11.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a".</p>
  </blockquote>
  
  <p>I use in both projects this app.config:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;configuration&gt;
    &lt;runtime&gt;
      &lt;assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1" xmlns:bcl="urn:schemas-microsoft-com:bcl"&gt;
        &lt;dependentAssembly bcl:name="System.Runtime"&gt;
          &lt;assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" /&gt;
          &lt;bindingRedirect oldVersion="0.0.0.0-2.5.16.0" newVersion="2.5.16.0" /&gt;
        &lt;/dependentAssembly&gt;
        &lt;dependentAssembly&gt;
          &lt;assemblyIdentity name="System.Threading.Tasks" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" /&gt;
          &lt;bindingRedirect oldVersion="0.0.0.0-2.5.16.0" newVersion="2.5.16.0" /&gt;
        &lt;/dependentAssembly&gt;
      &lt;/assemblyBinding&gt;
    &lt;/runtime&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>What I'm doing wrong?</p>
  
  <p>I don't want to reference the async package dlls.</p>
  
  <p>I can't use .Net 4.5 target. It must be .Net 4.</p>
  
  <p>Target Framework for all projects: .NET Framework 4</p>