Add sample config and the option to speak repeated lines at a faster rate

src/kokoro.rs

@@ -37,6 +37,7 @@ struct SpeechRequest<'a> {
     voice: &'a str,
     model: &'static str,
     response_format: &'static str,
+    speed: f32,
     stream: bool,
 }
 
@@ -82,7 +83,7 @@ impl KokoroClient {
             .collect())
     }
 
-    pub async fn synthesize_wav(&self, text: &str, voice: &str) -> Result<Vec<u8>> {
+    pub async fn synthesize_wav(&self, text: &str, voice: &str, speed: f32) -> Result<Vec<u8>> {
         let response = self
             .client
             .post(self.endpoint("v1/audio/speech")?)
@@ -91,6 +92,7 @@ impl KokoroClient {
                 voice,
                 model: "kokoro",
                 response_format: "wav",
+                speed,
                 stream: false,
             })
             .send()
@@ -156,12 +158,25 @@ mod tests {
         let url = serve_once("200 OK", "audio/wav", b"RIFFmock");
         let wav = KokoroClient::new(&url)
             .unwrap()
-            .synthesize_wav("hello", "af_heart")
+            .synthesize_wav("hello", "af_heart", 1.0)
             .await
             .unwrap();
         assert_eq!(wav, b"RIFFmock");
     }
 
+    #[test]
+    fn speech_request_includes_speed() {
+        let request = SpeechRequest {
+            input: "hello",
+            voice: "af_heart",
+            model: "kokoro",
+            response_format: "wav",
+            speed: 1.5,
+            stream: false,
+        };
+        assert_eq!(serde_json::to_value(request).unwrap()["speed"], 1.5);
+    }
+
     #[tokio::test]
     async fn treats_non_success_as_failure() {
         let url = serve_once("503 Service Unavailable", "application/json", b"{}");