Use mem::replace instead of cloning.

Author: illegalprime

src/receiver.rs

@@ -132,10 +132,6 @@ impl ws::Receiver for Receiver {
 			}
 		}
 
-		// TODO: this is slow, easy fix
-		let buffer = self.buffer.clone();
-		self.buffer.clear();
-
-		Ok(buffer)
+    Ok(::std::mem::replace(&mut self.buffer, Vec::new()))
 	}
 }