Managing memory leaks in Rust with a long-running async task using Tokio
I've searched everywhere and can't find a clear answer. I've looked through the documentation and I'm still confused about I'm working on a long-running async task in Rust using the Tokio runtime, and I'm encountering what seems to be a memory leak. The task is meant to poll a remote service periodically and cache the results in a `HashMap`. However, after several hours of running, the application's memory usage continues to grow significantly. I've set up the async task like this: ```rust use std::collections::HashMap; use tokio::time::{sleep, Duration}; struct Cache { data: HashMap<String, String>, } impl Cache { fn new() -> Self { Self { data: HashMap::new() } } async fn update(&mut self) { // Fetch new data from a remote service. // Simulating with a sleep and a dummy update. sleep(Duration::from_secs(5)).await; self.data.insert("key".to_string(), "value".to_string()); } } #[tokio::main] async fn main() { let mut cache = Cache::new(); loop { cache.update().await; } } ``` I have already checked that I'm not holding onto unnecessary references or data that aren't needed. The `Cache` struct is being created once, and the `update` method is simply modifying its `data` field. I also tried using `tokio::spawn` to run the update in a separate task, but that didn't seem to help either. When I monitor the memory usage, I see that it keeps increasing even though the `HashMap` should not be growing indefinitely. After about five hours, I noticed that it has increased from about 30MB to over 300MB, which is concerning. Could this be caused by some form of accumulation of old tasks or un-dropped futures? What are the best practices for managing memory in this kind of long-running async task with Tokio? Any insights or recommendations for debugging this would be greatly appreciated. Any examples would be super helpful.