[skip ci]Add rocksmq comments (#10925)

Signed-off-by: Nfishpenguin <kun.yu@zilliz.com>

internal/util/rocksmq/client/rocksmq/client_impl.go

@@ -43,6 +43,7 @@ func newClient(options ClientOptions) (*client, error) {
 	return c, nil
 }
 
+// CreateProducer create a rocksmq producer
 func (c *client) CreateProducer(options ProducerOptions) (Producer, error) {
 	// Create a producer
 	producer, err := newProducer(c, options)