Fix typo

Author: Daksh14

tokio/src/fs/read.rs

@@ -77,7 +77,12 @@ async fn read_uring(path: &Path) -> io::Result<Vec<u8>> {
 
     let file = OpenOptions::new().read(true).open(path).await?;
 
-    let size = 0;
+    let size = file
+        .metadata()
+        .await
+        .map(|m| m.len() as usize)
+        .ok()
+        .unwrap_or(0);
 
     let mut buf = Vec::with_capacity(size);