Use u32 instead of usize for PID

binaries/daemon/src/lib.rs

@@ -1330,7 +1330,7 @@ fn close_input(
 
 #[derive(Debug, Clone)]
 struct RunningNode {
-    pid: usize,
+    pid: u32,
 }
 
 pub struct RunningDataflow {
@@ -1444,7 +1444,7 @@ impl RunningDataflow {
             system.refresh_processes();
 
             for (node, node_details) in running_nodes.iter() {
-                if let Some(process) = system.process(Pid::from(node_details.pid.clone())) {
+                if let Some(process) = system.process(Pid::from(node_details.pid as usize)) {
                     process.kill();
                     warn!(
                         "{node} was killed due to not stopping within the {:#?} grace period",

binaries/daemon/src/spawn.rs

@@ -42,7 +42,7 @@ pub async fn spawn_node(
     daemon_tx: mpsc::Sender<Timestamped<Event>>,
     dataflow_descriptor: Descriptor,
     clock: Arc<HLC>,
-) -> eyre::Result<usize> {
+) -> eyre::Result<u32> {
     let node_id = node.id.clone();
     tracing::debug!("Spawning node `{dataflow_id}/{node_id}`");
 
@@ -264,7 +264,7 @@ pub async fn spawn_node(
         .expect("Failed to create log file");
     let mut child_stdout =
         tokio::io::BufReader::new(child.stdout.take().expect("failed to take stdout"));
-    let pid = child.id().unwrap() as usize; // Todo: Manage failure
+    let pid = child.id().unwrap();
     let stdout_tx = tx.clone();
 
     // Stdout listener stream