MigrateDatabaseTask.php

<?php

class MigrateDatabaseTask extends AsyncTask{
  public function __construct(MigrateProgress $progress){
    parent::__construct($progress);
  }
  public function onRun(){
    $input = new InputDataIterator();
    $output = new OutputWriter();
    foreach($input as $datum){
      $output->write($datum);
      $this->publishProgress($output->writtenSize() / $input->totalSize());
    }
  }
  public function onProgressUpdate(Server $server, float $progress){
    $this->peekLocal($server)->progress = $progress;
  }
  public function onCompletion(Server $server){
    $this->fetchLocal($server); // even if we don't use it, we still have to call this, or a NOTICE will be generated.
  }
}

class MigrateProgress{
  public $progress;
}

class MigarteInfoTask extends PluginTask{
  public $progress;
  public $player;
  
  public function onRun($ticks){
    if(!isset($this->player)) return;
    if(!$this->player->isOnline()) {
      unset($this->player);
      return;
    }
    $this->player->sendPopup("Progress: {$this->progress->progress}");
  }
}

$task = new MigrateProgress($main);
$task->progress = new MigrateProgress;
$task->player = $player;
$scheduler->scheduleRepeatingTask($task, 20);
$scheduler->scheduleAsyncTask(new MigrateDatabaseTask($task->progress));