Compatibility with unix:// sockets?

[attisan]

When listening on unix sockets startup fails with

Worker 4 failed: Amp\Parallel\Sync\ContextPanicError: Uncaught Amp\Socket\SocketException in child process or thread with message "Could not create server tcp:///var/www/project/tmp/php.sock: [Error: #0] Failed to parse address "/var/www/project/tmp/php.sock"" and code "0"; use Amp\Parallel\Sync\ContextPanicError::getOriginalTrace() for the stack trace in the child process or thread in /var/www/project/vendor/amphp/parallel/lib/Sync/ExitFailure.php:46
Stack trace:
#0 /var/www/project/vendor/amphp/parallel/lib/Sync/ExitFailure.php(39): Amp\Parallel\Sync\ExitFailure->createException()
#1 /var/www/project/vendor/amphp/parallel/lib/Context/Process.php(232): Amp\Parallel\Sync\ExitFailure->getResult()
#2 [internal function]: Amp\Parallel\Context\Process->Amp\Parallel\Context\{closure}()
#3 /var/www/project/vendor/amphp/amp/lib/Coroutine.php(118): Generator->send()
#4 /var/www/project/vendor/amphp/amp/lib/Internal/Placeholder.php(149): Amp\Coroutine->Amp\{closure}()
#5 /var/www/project/vendor/amphp/amp/lib/Coroutine.php(123): Amp\Coroutine->resolve()
#6 /var/www/project/vendor/amphp/amp/lib/Internal/Placeholder.php(149): Amp\Coroutine->Amp\{closure}()
#7 /var/www/project/vendor/amphp/amp/lib/Deferred.php(53): Amp\Promise@anonymous->resolve()
#8 /var/www/project/vendor/amphp/byte-stream/lib/ResourceInputStream.php(101): Amp\Deferred->resolve()
#9 /var/www/project/vendor/amphp/amp/lib/Loop/NativeDriver.php(327): Amp\ByteStream\ResourceInputStream::Amp\ByteStream\{closure}()
#10 /var/www/project/vendor/amphp/amp/lib/Loop/NativeDriver.php(127): Amp\Loop\NativeDriver->selectStreams()
#11 /var/www/project/vendor/amphp/amp/lib/Loop/Driver.php(138): Amp\Loop\NativeDriver->dispatch()
#12 /var/www/project/vendor/amphp/amp/lib/Loop/Driver.php(72): Amp\Loop\Driver->tick()
#13 /var/www/project/vendor/amphp/amp/lib/Loop.php(95): Amp\Loop\Driver->run()
#14 /var/www/project/vendor/amphp/cluster/bin/cluster(250): Amp\Loop::run()
#15 /var/www/project/vendor/bin/cluster(117): include('...')
#16 {main} [] []