As discussed in #2297:
Honestly I don't see a fit purpose for async saving at all. It should either always be synchronous or always asynchronous, and at the user's own option. However, this isn't currently possible because Config doesn't enable you to get the serialized content without writing it to disk.
Consider the following code:
```php
for($i = 0, $size = $this->getServer()->getAsyncPool()->getSize(); $i < $size; ++$i){
$this->getServer()->getAsyncPool()->submitTask(new class extends AsyncTask{
public function onRun(){
sleep(5);
}
});
}
$config = $this->getConfig();
$config->set("steve", "hi");
$config->save(true);
$config->set("steve", "bye");
$config->save(false);
```
Output:
```yml
---
steve: hi
...
```
Expected output:
```yml
---
steve: bye
...
```
Additionally, if your configs are causing you performance issues when you're saving, it's a clear sign that
a) you're saving too much
b) you're abusing configs and should consider using a database.
Configs should be used for _simple_ data which does not change much. Configuration is such that the _user_ is expected to be able to modify it. As such, it should never be an issue to save synchronously.
In the future, something like ReactPHP may be introduced to allow proper async saving. When this happens, async saving would always be sequential but non blocking. Using threads for this makes no sense.
This commit contains quite a few breaking changes with respect to how AsyncTasks are handled. This is necessary to allow separation of the ServerScheduler and the AsyncPool, because in the future the ServerScheduler may be removed and instead there will be isolated per-plugin sync-task schedulers - but we cannot have every plugin with its own worker pool for memory usage reasons if nothing else.
The following things have changed:
- ServerScheduler: scheduleAsyncTask(), scheduleAsyncTaskToWorker(), getAsyncTaskPoolSize(), increaseAsyncTaskPoolSize() and similar methods have all been removed. Additionally the static \$WORKERS field has been removed.
- Server: added API method getAsyncPool(). This grants you direct access to the server's AsyncPool. Calls to getScheduler()->scheduleAsyncTask() and scheduleAsyncTaskToWorker() should be replaced with getAsyncPool()->submitTask() and submitTaskToWorker() respectively.
FixesLegendOfMCPE/EssentialsPE#354
When the config file didn't exist, no type detection was performed. This resulted in the case statement for Config->save() falling through and not writing anything to the file.
All plugins will need to bump the API if they want to use this.
NOTE THAT THIS IS NOT THE FINAL API 2.0.0 AND THAT THERE WILL BE MORE CHANGES.
To start updating, you might also want to read https://secure.php.net/manual/en/migration70.php and specifically https://secure.php.net/manual/en/migration70.incompatible.php
To compile PHP7 with some of the required dependencies, use https://gist.github.com/shoghicp/166ab26ce5cc7a390f45
ONLY LINUX IS TESTED, DO NOT ASK FOR OTHER PLATFORMS!
----- THIS VERSION IS NOT SUPPORTED -----
This version WILL crash randomly in unexpected places due to PHP7, pthreads, PocketMine or cosmic rays.
Handle with care, and store under direct sunlight for the best performance.
