added key to getHostname to get hostname from ShardedClient

Author: matthi4s

src/Client.php

@@ -72,7 +72,11 @@ public function __construct($hostname = "localhost:2379", $username = false, $pa
         $this->password = $password;
     }
 
-    public function getHostname(): string
+    /**
+     * @param string|null $key
+     * @return string
+     */
+    public function getHostname(?string $key = null): string
     {
         return $this->hostname;
     }

src/ClientInterface.php

@@ -11,7 +11,11 @@
  */
 interface ClientInterface
 {
-    public function getHostname(): string;
+    /**
+     * @param string|null $key
+     * @return string
+     */
+    public function getHostname(?string $key = null): string;
 
     /**
      * Put a value into the key store

src/ShardedClient.php

@@ -69,9 +69,15 @@ protected function getClientFromKey(string $key): ClientInterface
         return $this->keyCache[$key];
     }
 
-
-    public function getHostname(): string
+    /**
+     * @inheritDoc
+     * @throws \Flexihash\Exception
+     */
+    public function getHostname(?string $key = null): string
     {
+        if ($key) {
+            return $this->getClientFromKey($key)->getHostname($key);
+        }
         return implode("-", array_keys($this->clients));
     }