Delegates to $browser.defer, but wraps the fn function
into a try/catch block and delegates any exceptions to
$exceptionHandler service.
In tests you can use $browser.defer.flush() to flush the queue of deferred functions.
$defer(fn[, delay]);
fn – {function()} –
A function, who's execution should be deferred.
delay(optional=0) – {number} –
of milliseconds to defer the function execution.