Actix Web Rustls v0.21 support (#3116)

actix-router/src/url.rs

@@ -62,6 +62,8 @@ impl ResourcePath for Url {
 
 #[cfg(test)]
 mod tests {
+    use std::fmt::Write as _;
+
     use http::Uri;
 
     use super::*;
@@ -78,7 +80,11 @@ mod tests {
     }
 
     fn percent_encode(data: &[u8]) -> String {
-        data.iter().map(|c| format!("%{:02X}", c)).collect()
+        data.iter()
+            .fold(String::with_capacity(data.len() * 3), |mut buf, c| {
+                write!(&mut buf, "%{:02X}", c).unwrap();
+                buf
+            })
     }
 
     #[test]