How to reproduce:

1. Open attached project
2. Open scene test.unity
3. Select the Main Camera gameobject
4. In the Proto Test component add 'testFile' in the Filename text box
5. Build to iOS and run
- Note the error:
ArgumentException: Get Method not found for 'SkipConstructor'
at System.Reflection.MonoProperty.GetValue (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] index, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0
at System.Reflection.MonoProperty.GetValue (System.Object obj, System.Object[] index) [0x00000] in <filename unknown>:0
at ProtoBuf.Meta.AttributeMap+ReflectionAttributeMap.TryGet (System.String key, Boolean publicOnly, System.Object& value)
[...]

Workaround the issue by adding a link.xml file to the project telling the code stripper to preserve the Attribute class in the protobuf-net assembly.