Why does Google prepend while(1); to their (private) JSON responses? For example, here's a response while turning a calendar on and off in Google Calendar: while (1); [ ['u', [ ['smsSentFlag', 'false'], ['hideInvitations', 'false'], ['remindOnRespondedEventsOnly', 'true'], ['hideInvitations_remindOnRespondedEventsOnly', 'false_true'], ['Calendar ID stripped for privacy', 'false'], ['smsVerifiedFla