Fix large RetryError clippy warnings

Clippy is warning that the size of RetryError (both proto and quinn's
versions) are excessively large for a Result Err variant. This function
fixes these warnings by boxing the contents of both.

Author: gretchenfrage

quinn-proto/src/endpoint.rs

@@ -723,7 +723,7 @@ impl Endpoint {
     /// Errors if `incoming.may_retry()` is false.
     pub fn retry(&mut self, incoming: Incoming, buf: &mut Vec<u8>) -> Result<Transmit, RetryError> {
         if !incoming.may_retry() {
-            return Err(RetryError(incoming));
+            return Err(RetryError(Box::new(incoming)));
         }
 
         self.clean_up_incoming(&incoming);
@@ -1278,12 +1278,12 @@ pub struct AcceptError {
 /// Error for attempting to retry an [`Incoming`] which already bears a token from a previous retry
 #[derive(Debug, Error)]
 #[error("retry() with validated Incoming")]
-pub struct RetryError(Incoming);
+pub struct RetryError(Box<Incoming>);
 
 impl RetryError {
     /// Get the [`Incoming`]
     pub fn into_incoming(self) -> Incoming {
-        self.0
+        *self.0
     }
 }
 

quinn/src/incoming.rs

@@ -52,10 +52,10 @@ impl Incoming {
     pub fn retry(mut self) -> Result<(), RetryError> {
         let state = self.0.take().unwrap();
         state.endpoint.retry(state.inner).map_err(|e| {
-            RetryError(Self(Some(State {
+            RetryError(Box::new(Self(Some(State {
                 inner: e.into_incoming(),
                 endpoint: state.endpoint,
-            })))
+            }))))
         })
     }
 
@@ -118,12 +118,12 @@ struct State {
 /// Error for attempting to retry an [`Incoming`] which already bears a token from a previous retry
 #[derive(Debug, Error)]
 #[error("retry() with validated Incoming")]
-pub struct RetryError(Incoming);
+pub struct RetryError(Box<Incoming>);
 
 impl RetryError {
     /// Get the [`Incoming`]
     pub fn into_incoming(self) -> Incoming {
-        self.0
+        *self.0
     }
 }