code: public static DiffSet diffSet(GraphQLSchema schemaOld, GraphQLSchema schemaNew) {
          Map<String, Object> introspectionOld = introspect(schemaOld);
          Map<String, Object> introspectionNew = introspect(schemaNew);
          return diffSet(introspectionOld, introspectionNew);
      }
docs: Creates a diff set out of the result of 2 schemas.
  
  @param schemaOld the older schema
  @param schemaNew the newer schema
  
  @return a diff set representing them