THRIFT-4960 bare trait (dyn) warnings
Client: Rust
Patch: Danny Browning

This closes #1851
diff --git a/lib/rs/src/transport/buffered.rs b/lib/rs/src/transport/buffered.rs
index 87cfeff..b33eb4f 100644
--- a/lib/rs/src/transport/buffered.rs
+++ b/lib/rs/src/transport/buffered.rs
@@ -139,7 +139,7 @@
 
 impl TReadTransportFactory for TBufferedReadTransportFactory {
     /// Create a `TBufferedReadTransport`.
-    fn create(&self, channel: Box<Read + Send>) -> Box<TReadTransport + Send> {
+    fn create(&self, channel: Box<dyn Read + Send>) -> Box<dyn TReadTransport + Send> {
         Box::new(TBufferedReadTransport::new(channel))
     }
 }
@@ -254,7 +254,7 @@
 
 impl TWriteTransportFactory for TBufferedWriteTransportFactory {
     /// Create a `TBufferedWriteTransport`.
-    fn create(&self, channel: Box<Write + Send>) -> Box<TWriteTransport + Send> {
+    fn create(&self, channel: Box<dyn Write + Send>) -> Box<dyn TWriteTransport + Send> {
         Box::new(TBufferedWriteTransport::new(channel))
     }
 }