message: Fix example to correspond to new API.
diff: @@ -16,9 +16,9 @@ public:
  explicit ExampleContext(uint32_t id, RootContext* root) : Context(id, root) {}
  void onCreate() override;
  - FilterHeadersStatus onRequestHeaders(uint32_t headers) override;
  + FilterHeadersStatus onRequestHeaders(uint32_t headers, bool end_of_stream) override;
  FilterDataStatus onRequestBody(size_t body_buffer_length, bool end_of_stream) override;
  - FilterHeadersStatus onResponseHeaders(uint32_t headers) override;
  + FilterHeadersStatus onResponseHeaders(uint32_t headers, bool end_of_stream) override;
  void onDone() override;
  void onLog() override;
  void onDelete() override;
  @@ -34,7 +34,7 @@ bool ExampleRootContext::onStart(size_t) {
  void ExampleContext::onCreate() { LOG_WARN(std::string("onCreate " + std::to_string(id()))); }
  -FilterHeadersStatus ExampleContext::onRequestHeaders(uint32_t) {
  +FilterHeadersStatus ExampleContext::onRequestHeaders(uint32_t, bool) {
  LOG_DEBUG(std::string("onRequestHeaders ") + std::to_string(id()));
  auto result = getRequestHeaderPairs();
  auto pairs = result->pairs();
  @@ -45,7 +45,7 @@ FilterHeadersStatus ExampleContext::onRequestHeaders(uint32_t) {
  return FilterHeadersStatus::Continue;
  }
  -FilterHeadersStatus ExampleContext::onResponseHeaders(uint32_t) {
  +FilterHeadersStatus ExampleContext::onResponseHeaders(uint32_t, bool) {
  LOG_DEBUG(std::string("onResponseHeaders ") + std::to_string(id()));
  auto result = getResponseHeaderPairs();
  auto pairs = result->pairs();
  