@Test
        @DisplayName("Should handle deeply nested exceptions")
        void testToStringWithNestedExceptions() {
            Exception innermost = new IOException("Innermost exception");
            Exception middle = new RuntimeException("Middle exception", innermost);
            Exception rootCause = new IllegalStateException("Outer exception", middle);

When you add multiple middlewares using either `@app.middleware()` decorator or `app.add_middleware()` method, each new middleware wraps the application, forming a stack. The last middleware added is the *outermost*, and the first is the *innermost*.

On the request path, the *outermost* middleware runs first.

On the response path, it runs last.

For example:

```Python
app.add_middleware(MiddlewareA)
app.add_middleware(MiddlewareB)
```

  @GwtIncompatible
  @Deprecated
  public static RuntimeException propagate(Throwable throwable) {
    throwIfUnchecked(throwable);
    throw new RuntimeException(throwable);
  }

  /**
   * Returns the innermost cause of {@code throwable}. The first throwable in a chain provides
   * context from when the error or exception was initially detected. Example usage:
   *
   * <pre>

            new TestStringListGenerator() {
              @Override
              public List<String> create(String[] elements) {
                List<String> innerList = new ArrayList<>();
                Collections.addAll(innerList, elements);
                return unmodifiableList(innerList);
              }
            })
        .named("unmodifiableList/ArrayList")
        .withFeatures(
            CollectionFeature.SERIALIZABLE,