https://mo8it.com/blog/faster-rust-serialization/

json_fast_serializer.rs

// [dependencies]
// serde = { version = "1.0.193", features = [] }
// serde_json = { version = "1.0.108", features = [] }

use serde::{Serialize, Serializer};
use std::fmt;

struct Name {
    first_name: String,
    last_name: String,
}

impl fmt::Display for Name {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{} {}", self.first_name, self.last_name)
    }
}

// Implement Serialize to customize JSON serialization
// Use serializer.collect_str() to append to buffer directly
impl Serialize for Name {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: Serializer,
    {
        serializer.collect_str(&self)
    }
}


fn serialize_names(names: &[Name]) -> serde_json::Result<String> {
    serde_json::to_string(names)
}


fn main() {
    let names = vec![
        Name {
            first_name: "John".to_string(),
            last_name: "Doe".to_string(),
        },
        Name {
            first_name: "Jane".to_string(),
            last_name: "Doe".to_string(),
        }
    ];

    let json = serialize_names(&names).unwrap();
    println!("{}", json);
}