Replace mem::replace with assignment

Co-Authored-By: Nicolas Koch <nioko1337@googlemail.com>

Author: gridbugs

src/source/buffered.rs

@@ -87,7 +87,7 @@ where
                     if let Frame::Data(next_data) = next {
                         // Swap the current FrameData with the next one, allowing the current one
                         // to go out of scope.
-                        mem::replace(self, next_data);
+                        *self = next_data;
                     } else {
                         break;
                     }