share voice problem

configs.go

@@ -480,6 +480,10 @@ func (config VoiceConfig) values() (url.Values, error) {
 		v.Add("duration", strconv.Itoa(config.Duration))
 	}
 
+	if config.Caption != "" {
+		v.Add("caption", config.Caption)
+	}
+
 	return v, nil
 }
 
@@ -491,6 +495,10 @@ func (config VoiceConfig) params() (map[string]string, error) {
 		params["duration"] = strconv.Itoa(config.Duration)
 	}
 
+	if config.Caption != "" {
+		params["caption"] = config.Caption
+	}
+
 	return params, nil
 }