Serde vec to Bson::Binary?

[JohanGoversTech]

Why convert a Vec<u8> not in a Bson::Binary?

#[test]
fn test_byte_array() {
	
	#[derive(Serialize, Deserialize, PartialEq, Debug)]
    struct Foo {
        a: Vec<u8>,
    }
	
	let foo = Foo { a: vec![100u8; 400]};
	
	let e = Encoder::new();
    let r = match foo.serialize(e) {
        Ok(b) => b,
        Err(e) => panic!("Failed to serialize: {}", e),
    };
    
    println!("result {:?}", r);
}

Result in the error:
thread 'test_byte_array' panicked at 'Failed to serialize: BSON does not support unsigned type', test.rs:88:19
I would expect a Bson::Binary element to be created.

[JohanGoversTech]

I found the solution, you have to use serde_bytes

#[test]
fn test_byte_array() {
	
    #[derive(Serialize, Deserialize, PartialEq, Debug)]
    struct Foo {
        #[serde(with = "serde_bytes")]
        a: Vec<u8>,
    }
	
    let foo = Foo { a: vec![100u8; 400]};
	
    let e = Encoder::new();
    let r = match foo.serialize(e) {
        Ok(b) => b,
        Err(e) => panic!("Failed to serialize: {}", e),
    };
    
    println!("result {:?}", r);
}