Fix build issue when using rd_kafka_message_latency in old rdkafka

include/cppkafka/macros.h

@@ -47,5 +47,6 @@
 #define RD_KAFKA_QUEUE_REFCOUNT_BUG_VERSION 0x000b0500 //v0.11.5.00
 #define RD_KAFKA_HEADERS_SUPPORT_VERSION 0x000b0402 //v0.11.4.02
 #define RD_KAFKA_ADMIN_API_SUPPORT_VERSION 0x000b0500 //v0.11.5.00
+#define RD_KAFKA_MESSAGE_LATENCY_SUPPORT_VERSION 0x000b0000 //v0.11.0.00
 
 #endif // CPPKAFKA_MACROS_H

include/cppkafka/message.h

@@ -177,6 +177,7 @@ public:
      */
     boost::optional<MessageTimestamp> get_timestamp() const;
     
+#if RD_KAFKA_VERSION >= RD_KAFKA_MESSAGE_LATENCY_SUPPORT_VERSION
     /**
      * \brief Gets the message latency in microseconds as measured from the produce() call.
      */
@@ -184,6 +185,7 @@ public:
         assert(handle_);
         return std::chrono::microseconds(rd_kafka_message_latency(handle_.get()));
     }
+#endif
 
     /**
      * \brief Indicates whether this message is valid (not null)