private function failAll()
{
if ($this->writeWatcher !== null) {
\Amp\cancel($this->writeWatcher);
}
$this->sock = $this->writeWatcher = null;
$promisors = $this->promisors;
$this->promisors = [];
foreach ($promisors as $deferred) {
$deferred->fail(new \Exception("Couldn't write command, server failed."));
}
}