Remove runOnIdleState functionality

api/src/main/java/io/camunda/zeebe/process/test/api/InMemoryEngine.java

@@ -29,15 +29,6 @@ public interface InMemoryEngine {
    */
   void increaseTime(Duration timeToAdd);
 
-  /**
-   * Runs the given function once the engine has reached an idle state.
-   *
-   * <p>For more info on the idle state refer to {@link IdleStateMonitor}
-   *
-   * @param callback the function that should be executed once an idle state has been reached
-   */
-  void runOnIdleState(Runnable callback);
-
   /**
    * Waits for the engine to reach an idle state.
    *

engine/src/main/java/io/camunda/zeebe/process/test/engine/InMemoryEngineImpl.java

@@ -101,16 +101,11 @@ public void increaseTime(final Duration timeToAdd) {
     clock.addTime(timeToAdd);
   }
 
-  @Override
-  public void runOnIdleState(final Runnable callback) {
-    idleStateMonitor.addCallback(callback);
-  }
-
   @Override
   public void waitForIdleState() {
     final CompletableFuture<Void> idleState = new CompletableFuture<>();
 
-    runOnIdleState(() -> idleState.complete(null));
+    idleStateMonitor.addCallback(() -> idleState.complete(null));
 
     idleState.join();
   }

extension-testcontainer/src/main/java/io.camunda.zeebe.process.test.extension.testcontainer/ContainerizedEngine.java

@@ -122,11 +122,6 @@ public void increaseTime(final Duration timeToAdd) {
     closeChannel(channel);
   }
 
-  @Override
-  public void runOnIdleState(final Runnable callback) {
-    // TODO remove this from interface?
-  }
-
   @Override
   public void waitForIdleState() {
     final ManagedChannel channel = getChannel();