don't construct the timezone every time a screenshot request is made

src/main.rs

@@ -6,6 +6,8 @@ use tokio::task::JoinHandle;
 use tracing::{Instrument, Level};
 use tracing_subscriber::FmtSubscriber;
 
+use tzfile::{ArcTz, Tz};
+
 use serde::Deserialize;
 use toml;
 
@@ -62,6 +64,8 @@ async fn main() -> anyhow::Result<()> {
     // Essentially this is meant to be a sentinel for "SCREENSHOT NOW!"
     let (tx, _) = tokio::sync::broadcast::channel::<Option<()>>(10);
 
+    let gmt_timezone = ArcTz::new(Tz::named("GMT")?);
+
     for (id, node) in config.vms.iter() {
         tracing::info!("Adding node {id} : {:?}", node);
 
@@ -70,12 +74,13 @@ async fn main() -> anyhow::Result<()> {
         let node_clone = node.clone();
         let root = config.root_path.clone();
 
+        let tz = gmt_timezone.clone();
+
         let _: JoinHandle<anyhow::Result<()>> = tokio::spawn(async move {
             while let Some(_) = _rx.recv().await? {
                 let span = tracing::span!(Level::INFO, "node screenshot", node = id_clone.as_str());
 
-                let zone = tzfile::Tz::named("GMT")?;
-                let now = { chrono::Utc::now().with_timezone(&&zone) };
+                let now = { chrono::Utc::now().with_timezone(&tz) };
 
                 let date_path = root.join(format!(
                     "{:02}-{:02}-{:02}",