Add retry_period option for email transport

Tests/TransportTest.php

@@ -58,6 +58,11 @@ public static function fromStringProvider(): iterable
             'roundrobin(dummy://a failover(dummy://b dummy://a) dummy://b)',
             new RoundRobinTransport([$transportA, new FailoverTransport([$transportB, $transportA]), $transportB]),
         ];
+
+        yield 'round robin transport with retry period' => [
+            'roundrobin(dummy://a dummy://b)?retry_period=15',
+            new RoundRobinTransport([$transportA, $transportB], 15),
+        ];
     }
 
     /**

Transport.php

@@ -107,7 +107,8 @@ public function fromStrings(#[\SensitiveParameter] array $dsns): Transports
     public function fromString(#[\SensitiveParameter] string $dsn): TransportInterface
     {
         [$transport, $offset] = $this->parseDsn($dsn);
-        if ($offset !== \strlen($dsn)) {
+        $dnsWithoutMainOptions = preg_replace('/[?&]retry_period=\d+/', '', $dsn);
+        if ($offset !== \strlen($dnsWithoutMainOptions)) {
             throw new InvalidArgumentException('The mailer DSN has some garbage at the end.');
         }
 
@@ -121,6 +122,10 @@ private function parseDsn(#[\SensitiveParameter] string $dsn, int $offset = 0):
             'roundrobin' => RoundRobinTransport::class,
         ];
 
+        $parsedUrl = parse_url($dsn);
+        parse_str($parsedUrl['query'] ?? '', $query);
+        $retryPeriod = min((int) ($query['retry_period'] ?? 60), 60);
+
         while (true) {
             foreach ($keywords as $name => $class) {
                 $name .= '(';
@@ -145,7 +150,7 @@ private function parseDsn(#[\SensitiveParameter] string $dsn, int $offset = 0):
                         }
                     }
 
-                    return [new $class($args), $offset];
+                    return [new $class($args, $retryPeriod), $offset];
                 }
             }