function until(test, fn, callback) {
    whilst(function () {
        return !test.apply(this, arguments);
    }, fn, callback);
}
Repeatedly call `fn` until `test` returns `true`. Calls `callback` when
stopped, or an error occurs. `callback` will be passed an error and any
arguments passed to the final `fn`'s callback.

The inverse of [whilst]{@link module:ControlFlow.whilst}.

@name until
@static
@memberOf module:ControlFlow
@method
@see [async.whilst]{@link module:ControlFlow.whilst}
@category Control Flow
@param {Function} test - synchronous truth test to perform before each
execution of `fn`. Invoked with ().
@param {Function} fn - A function which is called each time `test` fails.
The function is passed a `callback(err)`, which must be called once it has
completed with an optional `err` argument. Invoked with (callback).
@param {Function} [callback] - A callback which is called after the test
function has passed and repeated execution of `fn` has stopped. `callback`
will be passed an error and any arguments passed to the final `fn`'s
callback. Invoked with (err, [results]);