// An absent optional is represented as the JSON `null` and a present
// optional is represented as just the contained value.
//
// As commented in `Serializer` implementation, this is a lossy
// representation. For example the values `Some(())` and `None` both
// serialize as just `null`. Unfortunately this is typically what people
// expect when working with JSON. Other formats are encouraged to behave
// more intelligently if possible.
An absent optional is represented as the JSON `null` and a present
optional is represented as just the contained value.

As commented in `Serializer` implementation, this is a lossy
representation.
An absent optional is represented as the JSON ` null ` and a present optional is represented as just the contained value . As commented in ` Serializer ` implementation this is a lossy representation .
fn deserialize_option<V>(self, _visitor: V) -> Result<V::Value>
    where
        V: Visitor<'de>,
    {
        // if self.input.starts_with("null") {
        //     self.input = &self.input["null".len()..];
        //     visitor.visit_none()
        // } else {
        //     visitor.visit_some(self)
        // }
        unimplemented!()
    }
fn deserialize_option < V > ( self , _visitor : V ) -> Result < V :: Value > where V : Visitor < ' de > , { // if self.input.starts_with("null") { //     self.input = &self.input["null".len()..]; //     visitor.visit_none() // } else { //     visitor.visit_some(self) // } unimplemented ! ( ) }
An absent optional is represented as the JSON `null` and a present
optional is represented as just the contained value.
An absent optional is represented as the JSON ` null ` and a present optional is represented as just the contained value .
self
_visitor
V