Interop\Async\Loop::onReadable PHP Method

    public static function onReadable($stream, callable $callback, $data = null)
    {
        $driver = self::$driver ?: self::get();
        return $driver->onReadable($stream, $callback, $data);
    }

 public function read(int $length = 8192) : Awaitable
 {
     if (!$this->readerEnabled) {
         $len = \strlen($this->readBuffer);
         try {
             $chunk = $this->fillReadBuffer($len, $length);
         } catch (\Throwable $e) {
             return new Failure($e);
         }
         if ($chunk === null) {
             return new Success(null);
         }
         if ($chunk !== $this) {
             if ($len > $length) {
                 $this->readBuffer = \substr($chunk, $length);
                 return new Success(\substr($chunk, 0, $length));
             }
             $this->readBuffer = '';
             return new Success($chunk);
         }
         $this->readerEnabled = true;
         if ($this->pendingReads === null) {
             $this->pendingReads = new \SplQueue();
         }
         if ($this->readWatcher === null) {
             $this->readWatcher = Loop::onReadable($this->socket, $this->createReadWatcher());
         } else {
             try {
                 Loop::enable($this->readWatcher);
             } catch (InvalidWatcherException $e) {
                 $this->readWatcher = Loop::onReadable($this->socket, $this->createReadWatcher());
             }
         }
     }
     $this->pendingReads->enqueue($read = new PendingRead($length, function () {
         foreach ($this->pendingReads as $read) {
             if (!$read->disabled) {
                 return;
             }
         }
         $this->readerEnabled = false;
         Loop::disable($this->readWatcher);
     }));
     return $read;
 }