fix: ensure that resume doesn't hang the pipeline

Author: space-pope

src/main/java/io/spokestack/spokestack/SpeechPipeline.java

@@ -258,8 +258,13 @@ public void pause() {
     /**
      * Resumes a paused speech pipeline, returning the pipeline to a passive
      * listening state.
+     *
+     * Does nothing if the pipeline has not been previously paused.
      */
     public void resume() {
+        if (!this.paused) {
+            return;
+        }
         this.paused = false;
         synchronized (lock) {
             lock.notify();

src/test/java/io/spokestack/spokestack/SpeechPipelineTest.java

@@ -223,6 +223,9 @@ public void testPause() throws Exception {
         Thread.sleep(5);
         assertTrue(FreeInput.counter > frames);
 
+        // resume before pause doesn't cause any hangs
+        pipeline.resume();
+
         // we won't get any more frames if we're paused
         pipeline.pause();