title: Generate random string with FsCheck using C#
body: <p>I'd like to gradually integrate FsCheck in my C# test code (as first step).</p>
  
  <p>I'd like to randomly generate part of my input data.</p>
  
  <p>This is how I generate a random string:</p>
  
  <pre><code>
  static string RandomString() {
    var kgen = Gen.Constant(Gen.Sized(g => Gen.OneOf(Arb.Generate())));
    var sgen = Gen.Sample(1, 10, kgen).First();
    var str = Gen.Eval(10, Random.StdGen.NewStdGen(0, 1000), sgen);
    return str;
  }
  </code></pre>
  
  <p>If I call it multiple times, I get each time the same string.</p>
  
  <p>How can I get a different string each time and/or correctly writing this code?</p>