Handler must be Sync to send the Client to another thread
@@ -65,7 +65,7 @@ impl Handlers {
}
/// Handler allows you to implement message filtering with a struct
#[allow(unused_variables)]
-pub trait Handler {
+pub trait Handler: Send {
/// Called when a [`Message`](./enum.Message.html) message is received
#[inline]
fn on_message(&mut self, msg: Arc<Message>) {
