scientific notation optional leading zeros in the exponent

[Bollie15]

Both 9e-05 and 9e-5 mean the same thing in scientific notation, as leading zeros in the exponent are optional.

use serde_json::{from_str, json, to_string, Value};

fn main() {
    let json_str = r#"{"a":9e-05}"#;
    let json_val: Value = from_str(json_str).unwrap();
    // println!("{}", to_string(&json_val).unwrap());
    println!("{}", json_val.to_string());
    assert_eq!(
        to_string(&json_val).unwrap(),
        json_str
    );
}

{"a":0.00009}
thread 'main' panicked at src/main.rs:17:5:
assertion `left == right` failed
  left: "{\"a\":0.00009}"
 right: "{\"a\":9e-05}"

[package]
name = "serde_float"
version = "0.1.0"
edition = "2021"

[dependencies]
serde_json = {version = "1.0", features = ["preserve_order"] }

[Bollie15]

How can I specify a floating point number to output in scientific notation?
"{"a":9e-05}" in, and "{"a":9e-05}" out