Как пример жёсткого костылинга

class PollingSocketPrototype implements \ATL\ITask { use \ATL\TTask; } # bring in Task class first as first level parent

class PollingSocketPrototype2 extends \ATL\Socket\PollingSocketPrototype implements \ATL\ISocket { use \ATL\TSocket; } # bring in base Socket class as second level parent

abstract class PollingSocket extends \ATL\Socket\PollingSocketPrototype2 implements \ATL\Socket\IPollingSocket { use \ATL\Socket\TPollingSocket; }

abstract class StreamBasePrototype extends \ATL\Socket\PollingSocket implements \ATL\Socket\Capabilities\IBulk { use \ATL\Socket\Capabilities\TBulk; }

abstract class StreamBase extends \ATL\Socket\StreamBasePrototype
{
...
}

abstract class StreamPrototype extends \ATL\Socket\StreamBase implements \ATL\Socket\Capabilities\IReadBytes, \ATL\Socket\Capabilities\IDelimitedReads
{
    use \ATL\Socket\Capabilities\TReadBytes; # bring in readBytes capability
    use \ATL\Socket\Capabilities\TDelimitedReads; # bring in delimited reads capability
}

class Stream extends \ATL\Socket\StreamPrototype
{
...
}

Всё вот это вот решилось бы множественным наследованием легко и просто.