Don't close in connection. It's closed explicitly on client side or implicitly in Server.open.

ioquatix · ioquatix · commit 31abe545afdb · 2018-07-05T10:48:55.000+12:00
diff --git a/lib/async/websocket/connection.rb b/lib/async/websocket/connection.rb
@@ -95,7 +95,6 @@ def write(data)
 			
 			def close
 				@driver.close
-				@socket.close
 			end
 		end
 	end
