It is my pleasure to introduce you 
Jazz 
made @ Anvil Research - a small repo demonstrating a new spooky pattern.
Example - delay
// Our function using jazz.delay
public shared({caller}) func first_example() : async () {
var unforgettable = "Something else";
// This function will execute after 5 seconds
jazz.delay(5, func() : () {
unforgettable := unforgettable # " Whee"; // our delayed function will have access to parent scope variable
te := unforgettable; // lets set te so the public get function can confirm our function executed
});
// this function will exit right away, wont wait for delay
};
Example - retry
//Our function using jazz.retry. To see it in action, repeatedly call 'get' function after calling `second_example`
public shared({caller}) func second_example() : async () {
te := "Let's go...";
// This function will execute up to 3 times with 5 seconds interval. If it returns `true` there will be no more retrying
ignore jazz.retry(3, 5, func() : async Bool {
te := te # " # ";
false;
});
// this function will exit after first try, rest will run later
};
How does it work
Anonymous functions are added to memory. Heartbeat executes them later.
Currently it’s for demo purposes and to help IC figure how to improve heartbeat @ulan. This suggested solution will probably work best for this pattern ic0.pause_heartbeat_until(absolute_time)
Doesn’t have a very good memory management and costs a lot.
You can use the pattern in production if you truly understand whats happening under the hood.
Usecase
These will be pretty useful when trying to solve tokenization related problems. @mariop For example - when notifying other canisters or adding transactions to history.
Future
These are possible: Throttle, Interval, Debounce, Cron, Batch, Shared async callback, etc…
It makes a lot of new things possible.
