Make connect methods idempotent

src/Consumer.php

@@ -9,6 +9,7 @@ use Amp\Promise;
 use Nsq\Config\ClientConfig;
 use Nsq\Exception\ConsumerException;
 use Nsq\Frame\Response;
+use Nsq\Stream\NullStream;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
 use function Amp\asyncCall;
@@ -60,6 +61,11 @@ final class Consumer extends Connection implements ConsumerInterface
 
     public function connect(): Promise
     {
+        if (!$this->stream instanceof NullStream) {
+            return call(static function (): void {
+            });
+        }
+
         return call(function (): \Generator {
             yield parent::connect();
 
@@ -113,6 +119,8 @@ final class Consumer extends Connection implements ConsumerInterface
                         }
                     }
                 }
+
+                $this->stream = new NullStream();
             });
         });
     }