public DemoValueTypeValueMarshaler()
 {
     Int32Marshaler = JniRuntime.CurrentRuntime.ValueManager.GetValueMarshaler <int> ();
 }
 protected JniValueMarshalerContractTests(JniValueMarshaler <T> marshaler = null)
 {
     this.marshaler = marshaler ?? JniRuntime.CurrentRuntime.ValueManager.GetValueMarshaler <T> ();
 }