diff --git a/examples/hello_world.rs b/examples/hello_world.rs
index 27794b9..f5886ea 100644
--- a/examples/hello_world.rs
+++ b/examples/hello_world.rs
@@ -1,30 +1,39 @@
 use std::u8;
 
-use tts::TTS;
+use tts::*;
 
 fn main() -> Result<(), std::io::Error> {
     env_logger::init();
     let mut tts = TTS::default()?;
     tts.speak("Hello, world.", false)?;
-    let original_rate = tts.get_rate()?;
-    tts.speak(format!("Current rate: {}", original_rate), false)?;
-    tts.set_rate(u8::MAX)?;
-    tts.speak("This is very fast.", false)?;
-    tts.set_rate(0)?;
-    tts.speak("This is very slow.", false)?;
-    tts.set_rate(original_rate)?;
-    let original_pitch = tts.get_pitch()?;
-    tts.set_pitch(u8::MAX)?;
-    tts.speak("This is high-pitch.", false)?;
-    tts.set_pitch(0)?;
-    tts.speak("This is low pitch.", false)?;
-    tts.set_pitch(original_pitch)?;
-    let original_volume = tts.get_volume()?;
-    tts.set_volume(u8::MAX)?;
-    tts.speak("This is loud!", false)?;
-    tts.set_volume(0)?;
-    tts.speak("This is quiet.", false)?;
-    tts.set_volume(original_volume)?;
+    let Features { rate, .. } = tts.supported_features();
+    if rate {
+        let original_rate = tts.get_rate()?;
+        tts.speak(format!("Current rate: {}", original_rate), false)?;
+        tts.set_rate(u8::MAX)?;
+        tts.speak("This is very fast.", false)?;
+        tts.set_rate(0)?;
+        tts.speak("This is very slow.", false)?;
+        tts.set_rate(original_rate)?;
+    }
+    let Features { pitch, .. } = tts.supported_features();
+    if pitch {
+        let original_pitch = tts.get_pitch()?;
+        tts.set_pitch(u8::MAX)?;
+        tts.speak("This is high-pitch.", false)?;
+        tts.set_pitch(0)?;
+        tts.speak("This is low pitch.", false)?;
+        tts.set_pitch(original_pitch)?;
+    }
+    let Features { volume, .. } = tts.supported_features();
+    if volume {
+        let original_volume = tts.get_volume()?;
+        tts.set_volume(u8::MAX)?;
+        tts.speak("This is loud!", false)?;
+        tts.set_volume(0)?;
+        tts.speak("This is quiet.", false)?;
+        tts.set_volume(original_volume)?;
+    }
     tts.speak("Goodbye.", false)?;
     Ok(())
 }
diff --git a/src/lib.rs b/src/lib.rs
index 910eda9..1594f18 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -38,10 +38,10 @@ impl convert::From<Error> for io::Error {
 }
 
 pub struct Features {
-    stop: bool,
-    rate: bool,
-    pitch: bool,
-    volume: bool,
+    pub stop: bool,
+    pub rate: bool,
+    pub pitch: bool,
+    pub volume: bool,
 }
 
 pub trait Backend {
@@ -130,7 +130,9 @@ impl TTS {
      * Sets the desired speech rate.
      */
     pub fn set_rate(&mut self, rate: u8) -> Result<&Self, Error> {
-        let Features { rate: rate_feature, .. } = self.supported_features();
+        let Features {
+            rate: rate_feature, ..
+        } = self.supported_features();
         if rate_feature {
             self.0.set_rate(rate)?;
             Ok(self)
@@ -155,7 +157,10 @@ impl TTS {
      * Sets the desired speech pitch.
      */
     pub fn set_pitch(&mut self, pitch: u8) -> Result<&Self, Error> {
-        let Features { pitch: pitch_feature, .. } = self.supported_features();
+        let Features {
+            pitch: pitch_feature,
+            ..
+        } = self.supported_features();
         if pitch_feature {
             self.0.set_pitch(pitch)?;
             Ok(self)
@@ -180,7 +185,10 @@ impl TTS {
      * Sets the desired speech volume.
      */
     pub fn set_volume(&mut self, volume: u8) -> Result<&Self, Error> {
-        let Features { volume: volume_feature, .. } = self.supported_features();
+        let Features {
+            volume: volume_feature,
+            ..
+        } = self.supported_features();
         if volume_feature {
             self.0.set_volume(volume)?;
             Ok(self)