Serde根据“全局”运行时条件跳过字段序列化

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
struct Person {
    name: String,
    age: u32,
    #[serde(skip_serializing_if = "is_female")]
    gender: Option<String>,
}

fn is_female(gender: &Option<String>) -> bool {
    match gender {
        Some(g) => g == "female",
        None => false,
    }
}

fn main() {
    let person1 = Person {
        name: "Alice".to_string(),
        age: 25,
        gender: Some("female".to_string()),
    };

    let person2 = Person {
        name: "Bob".to_string(),
        age: 30,
        gender: None,
    };

    let serialized1 = serde_json::to_string(&person1).unwrap();
    let serialized2 = serde_json::to_string(&person2).unwrap();

    println!("Serialized person1: {}", serialized1);
    println!("Serialized person2: {}", serialized2);
}

Serialized person1: {"name":"Alice","age":25}
Serialized person2: {"name":"Bob","age":30,"gender":null}