use struct for toggle endpoint

client.go

@@ -75,9 +75,7 @@ func (s *Client) SetState(selector string, state *State) ([]Result, error) {
 }
 
 func (s *Client) Toggle(selector string, duration float64) ([]Result, error) {
-	m := make(map[string]interface{})
-	m["duration"] = duration
-	j, err := json.Marshal(m)
+	j, err := json.Marshal(&Toggle{Duration: duration})
 	if err != nil {
 		return nil, err
 	}

structs.go

@@ -28,6 +28,10 @@ type (
 	Result struct {
 		ID     string `json:"id"`
 		Label  string `json:"label"`
-		Status string `json:"status"`
+		Status Status `json:"status"`
+	}
+
+	Toggle struct {
+		Duration float64 `json:"duration,omitempty"`
 	}
 )