/**
* Execute a callback within the scope of an event loop driver.
*
* @param callable $callback The callback to execute.
* @param Driver $driver The event loop driver. If `null`, a new one is created from the set factory.
*
* @return void
*
* @see \Interop\Async\Loop::setFactory()
*/
public static function execute(callable $callback, Driver $driver = null)
{
$previousDriver = self::$driver;
self::$driver = $driver ?: self::createDriver();
self::$level++;
try {
self::$driver->defer($callback);
self::$driver->run();
} finally {
self::$driver = $previousDriver;
self::$level--;
}
}
