fix: append service.name to prevent it being overidden

[FinnDore]

It looks like the with_resource function overrides previous resources if called more than once leading to the service.name to be deleted :(.

Here's a small video of the current behaviour and the proposed fix. here's the repro

Kapture.2024-04-07.at.11.24.03.mp4

[FinnDore]

That's rough, couldn't get a unit test to run consistently. Guess the Otel stuff is doing stuff behind the scenes.

Kapture.2024-04-07.at.12.33.30.mp4

    #[tokio::test]
    async fn test_service_name_set() {
        let tracer = Builder::new()
            .with_token("xaat-fake-token")
            .with_dataset("fake-dataset")
            .no_env()
            .with_service_name("test")
            .tracer()
            .unwrap();
        let is_present = tracer.provider().filter(|p| {
            p.config()
                .resource
                .iter()
                .any(|(key, value)| key.as_str() == SERVICE_NAME && value.as_str() == "test")
        });

        is_present.expect("Service name not set");
    }

[Licenser]

Good catch! Thank you 😊