static Map<Method, Setter> toSetters(
      SetterFactory setterFactory, Target<?> target, Set<Method> methods) {
    Map<Method, Setter> result = new LinkedHashMap<Method, Setter>();
    for (Method method : methods) {
      method.setAccessible(true);
      result.put(method, setterFactory.create(target, method));
    }
    return result;
  }
Process all methods in the target so that appropriate setters are created.
hystrix/src/main/java/feign/hystrix/HystrixInvocationHandler.java