diff --git a/src/protocol/message.rs b/src/protocol/message.rs
index 8ee3eac..f7a4640 100644
--- a/src/protocol/message.rs
+++ b/src/protocol/message.rs
@@ -159,6 +159,7 @@ impl IncompleteMessage {
 }
 
 /// The type of incomplete message.
+#[derive(Copy, Clone)]
 pub enum IncompleteMessageType {
     Text,
     Binary,