discuss: Add custom location name support

[Xuanwo]

Hi @jswrenn, thank you for your work. Databend has greatly benefited from this project, and I wanted to express my gratitude before making any proposals.

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Databend currently users it's own fork developed by @zhang2014 that adding custom location name support so that we can inject location names at runtime:

impl TrySpawn for Runtime {
    #[track_caller]
    fn try_spawn<T>(&self, task: T) -> Result<JoinHandle<T::Output>>
    where
        T: Future + Send + 'static,
        T::Output: Send + 'static,
    {
        let task = ThreadTracker::tracking_future(task);
        let task = match ThreadTracker::query_id() {
            None => async_backtrace::location!(String::from(GLOBAL_TASK_DESC)).frame(task),
            Some(query_id) => {
                async_backtrace::location!(format!("Running query {} spawn task", query_id))
                    .frame(task)
            }
        };

        #[expect(clippy::disallowed_methods)]
        Ok(self.handle.spawn(task))
    }
}

Do you think this feature is a good addition? I'm willing to help implement it inside the upstream project under your guidance and design.