diff --git a/examples/Transport/Receiver/CollectionReceiver.php b/examples/Transport/Receiver/CollectionReceiver.php
index f2b7b5e6..84410b5d 100644
--- a/examples/Transport/Receiver/CollectionReceiver.php
+++ b/examples/Transport/Receiver/CollectionReceiver.php
@@ -4,30 +4,30 @@
 
 namespace Flow\Examples\Transport\Receiver;
 
-use Flow\EnvelopeTrait;
+use SplObjectStorage;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\Transport\Receiver\ReceiverInterface;
 
 class CollectionReceiver implements ReceiverInterface
 {
-    use EnvelopeTrait;
-
     /**
-     * @var array<mixed, ReceiverInterface>
+     * @var SplObjectStorage<Envelope, ReceiverInterface>
      */
-    private array $envelopePool;
+    private SplObjectStorage $envelopePool;
 
     /**
      * @param iterable<ReceiverInterface> $receivers
      */
-    public function __construct(private iterable $receivers) {}
+    public function __construct(private iterable $receivers)
+    {
+        $this->envelopePool = new SplObjectStorage();
+    }
 
     public function get(): iterable
     {
         foreach ($this->receivers as $receiver) {
             foreach ($receiver->get() as $envelope) {
-                $id = $this->getEnvelopeId($envelope);
-                $this->envelopePool[$id] = $receiver;
+                $this->envelopePool[$envelope] = $receiver;
                 yield $envelope;
             }
         }
@@ -35,13 +35,11 @@ public function get(): iterable
 
     public function ack(Envelope $envelope): void
     {
-        $id = $this->getEnvelopeId($envelope);
-        $this->envelopePool[$id]->ack($envelope);
+        $this->envelopePool[$envelope]->ack($envelope);
     }
 
     public function reject(Envelope $envelope): void
     {
-        $id = $this->getEnvelopeId($envelope);
-        $this->envelopePool[$id]->reject($envelope);
+        $this->envelopePool[$envelope]->reject($envelope);
     }
 }
diff --git a/examples/Transport/Sender/CollectionSender.php b/examples/Transport/Sender/CollectionSender.php
index b4382c6a..fcd9c52d 100644
--- a/examples/Transport/Sender/CollectionSender.php
+++ b/examples/Transport/Sender/CollectionSender.php
@@ -4,14 +4,11 @@
 
 namespace Flow\Examples\Transport\Sender;
 
-use Flow\EnvelopeTrait;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\Transport\Sender\SenderInterface;
 
 class CollectionSender implements SenderInterface
 {
-    use EnvelopeTrait;
-
     /**
      * @param iterable<SenderInterface> $senders
      */
diff --git a/examples/server.php b/examples/server.php
index 7f091463..3c3375f0 100644
--- a/examples/server.php
+++ b/examples/server.php
@@ -18,7 +18,7 @@
 use Flow\IpStrategy\MaxIpStrategy;
 use Symfony\Component\Messenger\Envelope;
 
-$driver = match (random_int(1, 1)) {
+$driver = match (random_int(1, 4)) {
     1 => new AmpDriver(),
     2 => new FiberDriver(),
     3 => new ReactDriver(),
diff --git a/src/Flow/TransportFlow.php b/src/Flow/TransportFlow.php
index b06955b3..8ab5a48e 100644
--- a/src/Flow/TransportFlow.php
+++ b/src/Flow/TransportFlow.php
@@ -10,7 +10,6 @@
 use Flow\DriverInterface;
 use Flow\FlowInterface;
 use Flow\Ip;
-use SplObjectStorage;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\Transport\Receiver\ReceiverInterface;
 use Symfony\Component\Messenger\Transport\Sender\SenderInterface;
diff --git a/tests/EnvelopeTraitTest.php b/tests/EnvelopeTraitTest.php
deleted file mode 100644
index 1b6b9a05..00000000
--- a/tests/EnvelopeTraitTest.php
+++ /dev/null
@@ -1,30 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Flow\Test;
-
-use Flow\EnvelopeTrait;
-use PHPUnit\Framework\TestCase;
-use RuntimeException;
-use stdClass;
-use Symfony\Component\Messenger\Envelope;
-use Symfony\Component\Messenger\Stamp\TransportMessageIdStamp;
-
-class EnvelopeTraitTest extends TestCase
-{
-    use EnvelopeTrait;
-
-    public function testGetIpId(): void
-    {
-        $ip = Envelope::wrap(new stdClass(), [new TransportMessageIdStamp('envelope_id_test')]);
-        self::assertSame('envelope_id_test', $this->getEnvelopeId($ip));
-    }
-
-    public function testGetIpIdWithoutId(): void
-    {
-        $envelope = new Envelope(new stdClass());
-        $this->expectException(RuntimeException::class);
-        $this->getEnvelopeId($envelope);
-    }
-}
diff --git a/tests/Examples/Transport/Receiver/CollectionReceiverTest.php b/tests/Examples/Transport/Receiver/CollectionReceiverTest.php
index 05e50589..23111da7 100644
--- a/tests/Examples/Transport/Receiver/CollectionReceiverTest.php
+++ b/tests/Examples/Transport/Receiver/CollectionReceiverTest.php
@@ -5,7 +5,6 @@
 namespace Flow\Test\Examples\Transport\Receiver;
 
 use ArrayObject;
-use Flow\EnvelopeTrait;
 use Flow\Examples\Transport\Receiver\CollectionReceiver;
 use PHPUnit\Framework\TestCase;
 use SplObjectStorage;
@@ -18,8 +17,6 @@
 
 class CollectionReceiverTest extends TestCase
 {
-    use EnvelopeTrait;
-
     /**
      * @param array<ReceiverInterface>                             $receivers
      * @param SplObjectStorage<ReceiverInterface, array<Envelope>> $expectedReceiversIps
@@ -35,11 +32,11 @@ public function testGet($receivers, $expectedReceiversIps): void
         foreach ($expectedReceiversIps as $receiver) {
             $expectedIps = $expectedReceiversIps[$receiver];
             foreach ($expectedIps as $envelope) {
-                $expectedIpIds[] = $this->getEnvelopeId($envelope);
+                $expectedIpIds[] = $this->getTransportMessageId($envelope);
             }
         }
         $envelopeIds = array_map(function (Envelope $envelope) {
-            return $this->getEnvelopeId($envelope);
+            return $this->getTransportMessageId($envelope);
         }, iterator_to_array($envelopes));
 
         $this->assertArraySimilar($expectedIpIds, $envelopeIds);
@@ -59,12 +56,12 @@ public function testAckAndReject($receivers, $expectedReceiversIps, $expectedAck
 
         $envelopes = $collectionReceiver->get();
         foreach ($envelopes as $envelope) {
-            $envelopeId = $this->getEnvelopeId($envelope);
+            $envelopeId = $this->getTransportMessageId($envelope);
             $expectedReceiver = null;
             foreach ($expectedReceiversIps as $receiver) {
                 $expectedIps = $expectedReceiversIps[$receiver];
                 foreach ($expectedIps as $expectedIp) {
-                    $expectedIpId = $this->getEnvelopeId($expectedIp);
+                    $expectedIpId = $this->getTransportMessageId($expectedIp);
                     if ($envelopeId === $expectedIpId) {
                         $expectedReceiver = $receiver;
 
@@ -104,8 +101,6 @@ public static function receiverProvider(): iterable
             }
 
             $receiver = new class($envelopes, $expectedAckIpsReceivers, $expectedRejectIpsReceivers) implements ReceiverInterface {
-                use EnvelopeTrait;
-
                 /**
                  * @param array<Envelope>                 $envelopes
                  * @param array<mixed, ReceiverInterface> $expectedAckIpsReceivers
@@ -138,15 +133,23 @@ public function getExpectedRejectIpsReceivers()
 
                 public function ack(Envelope $envelope): void
                 {
-                    $id = $this->getEnvelopeId($envelope);
+                    $id = $this->getTransportMessageId($envelope);
                     $this->expectedAckIpsReceivers[$id] = $this;
                 }
 
                 public function reject(Envelope $envelope): void
                 {
-                    $id = $this->getEnvelopeId($envelope);
+                    $id = $this->getTransportMessageId($envelope);
                     $this->expectedRejectIpsReceivers[$id] = $this;
                 }
+
+                private function getTransportMessageId(Envelope $envelope): string
+                {
+                    /** @var null|TransportMessageIdStamp $stamp */
+                    $stamp = $envelope->last(TransportMessageIdStamp::class);
+
+                    return $stamp ? $stamp->getId() : '';
+                }
             };
             $expectedReceiversIps->offsetSet($receiver, $envelopes);
             $receivers[] = $receiver;
@@ -178,4 +181,12 @@ protected function assertArraySimilar(array $expected, array $array): void
             }
         }
     }
+
+    private function getTransportMessageId(Envelope $envelope): string
+    {
+        /** @var null|TransportMessageIdStamp $stamp */
+        $stamp = $envelope->last(TransportMessageIdStamp::class);
+
+        return $stamp ? $stamp->getId() : '';
+    }
 }