@module {Object} can-event/async/async
@parent can-observables
@collection can-infrastructure

@description Makes the event system asynchronous. __WARNING:__ This is experimental technology.

@signature `Object`

The `can-event/async/async` module makes the event system asynchronous.  It:

 - Provides an [can-event/async/async.async] method which converts event binding and dispatching to happen asynchronously.
 - Provides [can-event/async/async.sync]  method which converts event binding and dispatching to happen synchronously.
 - Provides an asynchronous [can-event/async/async.dispatch], [can-event/async/async.queue],
  [can-event/async/async.addEventListener] and [can-event/async/async.removeEventListener].
 - Provides a [can-event/async/async.flush] which can be used to immediately run all tasks in the
   task queue.

@body

## Use

Use `can-event/async/async`'s `async` method to make event binding and
dispatching happen immediately following the current event loop.

```js
import canEvent from "can-event";
import canAsync from "can-event/async/async";
canAsync.async();

const obj = {};
Object.assign( obj, canEvent );

obj.addEventListener( "foo", function() {
	console.log( "heard foo" );
} );
obj.dispatch( "foo" );
console.log( "dispatched foo" );

// Logs -> "dispatched foo" then "heard foo"
```

This means you never have to call [can-event/batch/batch.start] and [can-event/batch/batch.stop]. Notice
that in the following example `"change"` is only fired once:

```js
import canAsync from "can-event/async/async";
canAsync.async();

import compute from "can-compute";

const first = compute( "Justin" );
const last = compute( "Meyer" );

const fullName = compute( function() {
	return first() + " " + last();
} );

fullName.on( "change", function( ev, newVal, oldVal ) {
	newVal; //-> "Payal Shah"
	oldVal; //-> "Justin Meyer"
} );

first( "Payal" );
last( "Shah" );
```