alternate implementation using Box<MessageSender> and clone

src/event/mod.rs

@@ -1,8 +1,8 @@
 use {Channel, User};
 
 #[derive(Clone)]
-pub enum Event<'a> {
-    Message { sender: User<'a>, channel: Option<Channel<'a>>, content: String },
-    Join { channel: Channel<'a> },
-    Quit { channel: Channel<'a> }
+pub enum Event {
+    Message { sender: User, channel: Option<Channel>, content: String },
+    Join { channel: Channel },
+    Quit { channel: Channel }
 }