Fields
- A field shall be a combination of getter, setter and notification event.
field应为getter，setter和notification事件的组合。 - A field without a setter and without a getter and without a notifier shall not exist. The field shall contain at least a getter, a setter, or a notifier.
不存在没有setter且没有getter且没有notifier的field。 该field应至少包含一个getter，一个setter或一个notifier。 - The getter of a field shall be a request/response call that has an empty payload in the request message and the value of the field in the payload of the response message.
field的getter应是一个请求/响应调用，其request消息中payload为空，response消息中payload中的值就是field的值。 - The setter of a field shall be a request/response call that has the desired value of the field in the payload of the request message and the value that was set to the field in the payload of the response message.
field的setter应是一个请求/响应调用，其将field的期望值放在request消息的payload中，这个值被设置到response消息的payload中。 - Note注意：
If the value of the request payload was adapted (e.g. because it was out of limits) the adapted value will be transported in the response payload.
如果request消息中 payload的值被调整了（例如，因为它超出限制），则这个调整后的值将放在response消息的有效载荷中发送。
The notifier shall send an event message that transports the value of a field on change and follows the rules for events.
如果该field的值改变，notifier应发送一个event消息以传输该值，当然，要遵循event规则。