putQueryParam should handle special serializable types #1783

putQueryParam should handle object types that are serializable, such as FieldMask, by using proper serialization rather than String.valueOf() which would produce an unprocessable url format (i.e. toJson()).

A valid query param can be a primitive OR an instance of Duration, Timestamp, FieldMask or *Value wrapper classes (like Int32Value). Specific details of serialization for each type are in the protobuf language guide