diff --git a/lib/landline/extensions/websocket.rb b/lib/landline/extensions/websocket.rb
index 0d15576..c3de1b6 100644
--- a/lib/landline/extensions/websocket.rb
+++ b/lib/landline/extensions/websocket.rb
@@ -188,6 +188,8 @@ module Landline
       def _process_events(next_frame)
         loop do
           frame = next_frame.call
+          return nil unless frame
+
           case frame.type
           when :binary, :text, :pong then return frame
           when :ping