title: How HTTP PUT should work
body: <p>For example, there is resource on URI: <code>/api/items/123</code></p>
  
  <p>Response body for GET request is <code>{"Id": "123", "Foo": "foo", "Bar": "bar"}</code></p>
  
  <p>I send PUT request. The body of it is <code>{"Bar": "newBarValue"}</code></p>
  
  <p>In case of this request body, should properties <strong>Id</strong> and <strong>Foo</strong> be removed? Or just <strong>Bar</strong> property should be modified? Or server should return error code?</p>