(string)$connection type casting  will cause Exception.

hi,

Check the code and found some exception when we used.

/src/nsqphp/nsqphp.php

` 
                    if ($this->logger) {
                        $this->logger->warn(sprintf('Error processing [%s] "%s": %s', (string)$connection, $msg->getId(), $e->getMessage()));
                    }`
  
 The $connection is an array. 
