   defmodule AuthenticationExtension do
     use Pixie.Extension
 
-    def handle %Event{message: %{ext: %{username: u, password: p}=message}}=event do
+    def incoming %Event{message: %{ext: %{username: u, password: p}=message}}=event do
       case User.authenticate username, password do
         :ok ->
           %{event | message: %{message | ext: nil}}

  to `nil`, likewise if you want to stop a response being sent to the client.
  You must *always* return a Pixie.Event struct from `handle/1`.
  """
  defcallback handle(event :: Pixie.Event.t) :: Pixie.Event.t
end

      end
    end

    def incoming %Event{}=event do
      %{event | response: %{response | error: "Authentication Failed"}}
    end
  ```
