protected function getOutputLogCallback(ConnectionInterface $connection, $level, $prefix = null)
{
$logger = $this->getLogger();
if (!method_exists($logger, $level)) {
throw new \DomainException("Invalid log level '{$level}'");
}
return function ($message) use($connection, $level, $prefix, $logger) {
$output = sprintf('%s %s%s', $connection->getMask(), $prefix, trim($message));
call_user_func(array($logger, $level), $output);
};
}