title: Sip client on Xamarin Studio
body: <p>We need to develop an application on three mobile <code>platforms</code>(<code>iOS</code>, <code>Android</code>, <code>WinPhone</code>), one of the feature of this application will be possibility to make sip calls(<code>voip</code>). 
  Is it possible to develop such application on <code>C#</code> using <code>Xamarin Studio</code>? Sip methods should be written on <code>C#, not ObjC,Java,C++</code>,etc. Has anyone positive or negative experience with same project? </p>