anchor.diff:      and a new pickler is constructed from that information. FsPickler can emit dynamic methods
       to ensure that no reflection or boxing penalty is incurred during actual serialization.
       Pickler generators can be further separated into the following kinds:
  -        - Field-based/struct pickler generation.
  +        - Field-based pickler generation.
           - DataContract pickler generation.
           - ISerializable pickler generation.
           - F# union/record/exception pickler generation.
  
positive.code: A managed class or struct is serializable if and only if it carries the `Serializable` attribute
  and moreover satisfies either of the following:
  
    * is abstract or a delegate.
  
    * is array/nullable/tuple/enum of serializable element types.
  
    * implements the `ISerializable` interface and has a matching constructor implementation.
  
negative.code:     serializable type and settable. Parameterless constructors or public properties are not required.
  
    * carries the [`CustomPickler`](reference/nessos-fspickler-custompicklerattribute.html) attribute and an accompanying pickler factory method.
  
    * is an F# union type in which all union case fields are serializable.
  
    * is abstract or a delegate.
  
    * is neither of the above and all designated fields are of serializable type.
      Parameterless constructors or public fields are not required.
  