diff --git a/headers/enduro2d/core/audio.hpp b/headers/enduro2d/core/audio.hpp
index 824dbe16..997e78fd 100644
--- a/headers/enduro2d/core/audio.hpp
+++ b/headers/enduro2d/core/audio.hpp
@@ -96,7 +96,7 @@ namespace e2d
 
         void volume(f32 value) noexcept;
         [[nodiscard]] f32 volume() const noexcept;
-        
+
         void resume() noexcept;
         void pause() noexcept;
     private:
diff --git a/headers/enduro2d/core/profiler.hpp b/headers/enduro2d/core/profiler.hpp
index 282d348d..d161231f 100644
--- a/headers/enduro2d/core/profiler.hpp
+++ b/headers/enduro2d/core/profiler.hpp
@@ -8,6 +8,8 @@
 
 #include "_core.hpp"
 
+#include "deferrer.hpp"
+
 namespace e2d
 {
     class profiler final : public module<profiler> {
@@ -156,7 +158,7 @@ namespace e2d
 
             void on_event(const event_info& event) noexcept final {
                 const bool skip = info_.events.empty() && depth_;
-                
+
                 if ( std::holds_alternative<begin_scope_info>(event) ) {
                     ++depth_;
                 } else if ( std::holds_alternative<end_scope_info>(event) ) {
@@ -168,7 +170,7 @@ namespace e2d
                     if ( !skip ) {
                         info_.events.push_back(event);
                     }
-                    
+
                     if ( !depth_ && time_point_ <= Clock::now() ) {
                         promise_.resolve(std::move(info_));
                     }
@@ -212,7 +214,7 @@ namespace e2d::profilers
     bool try_save_recording_info(
         const profiler::recording_info& src,
         buffer& dst) noexcept;
-    
+
     bool try_save_recording_info(
         const profiler::recording_info& src,
         const output_stream_uptr& dst) noexcept;
diff --git a/headers/enduro2d/core/render.hpp b/headers/enduro2d/core/render.hpp
index c535d7e2..adf88318 100644
--- a/headers/enduro2d/core/render.hpp
+++ b/headers/enduro2d/core/render.hpp
@@ -906,7 +906,7 @@ namespace e2d
         shader_ptr create_shader(
             str_view vertex_source,
             str_view fragment_source);
-        
+
         shader_ptr create_shader(
             buffer_view vertex_source,
             buffer_view fragment_source);
diff --git a/headers/enduro2d/core/window.hpp b/headers/enduro2d/core/window.hpp
index ddbb7501..f75bc306 100644
--- a/headers/enduro2d/core/window.hpp
+++ b/headers/enduro2d/core/window.hpp
@@ -105,7 +105,7 @@ namespace e2d
     private:
         debug& debug_;
     };
-    
+
     class window_input_source final : public window::event_listener {
     public:
         window_input_source(input& input) noexcept;
diff --git a/headers/enduro2d/utils/buffer_view.hpp b/headers/enduro2d/utils/buffer_view.hpp
index 7d2b81d1..be2294ed 100644
--- a/headers/enduro2d/utils/buffer_view.hpp
+++ b/headers/enduro2d/utils/buffer_view.hpp
@@ -61,7 +61,7 @@ namespace e2d
     buffer_view::buffer_view(const std::array<T,N>& buffer) noexcept
     : data_(buffer.data())
     , size_(buffer.size() * sizeof(T)) {}
-    
+
     template < typename T, std::size_t N >
     buffer_view::buffer_view(const T (&buffer)[N]) noexcept
     : data_(&buffer[0])
diff --git a/headers/enduro2d/utils/url.hpp b/headers/enduro2d/utils/url.hpp
index 4e1c5102..115961f1 100644
--- a/headers/enduro2d/utils/url.hpp
+++ b/headers/enduro2d/utils/url.hpp
@@ -38,7 +38,7 @@ namespace e2d
 
         const str& scheme() const noexcept;
         const str& path() const noexcept;
-        
+
         str schemepath() const;
 
         url& operator+=(str_view path);
diff --git a/samples/sources/sample_00/sample_00.cpp b/samples/sources/sample_00/sample_00.cpp
index a3ddca95..475374d9 100644
--- a/samples/sources/sample_00/sample_00.cpp
+++ b/samples/sources/sample_00/sample_00.cpp
@@ -96,7 +96,7 @@ namespace
             the<vfs>().register_scheme_alias(
                 "ships",
                 url("piratepack://PNG/Retina/Ships"));
-            
+
             image texture1_image;
             if ( !images::try_load_image(texture1_image, the<vfs>().read(url("ships://ship (2).png"))) ) {
                 return false;
diff --git a/samples/sources/sample_01/sample_01.cpp b/samples/sources/sample_01/sample_01.cpp
index 6e9a9930..7259897a 100644
--- a/samples/sources/sample_01/sample_01.cpp
+++ b/samples/sources/sample_01/sample_01.cpp
@@ -156,7 +156,7 @@ namespace
             the<vfs>().register_scheme_alias(
                 "ships",
                 url("piratepack://PNG/Retina/Ships"));
-            
+
             image texture_image;
             if ( !images::try_load_image(texture_image, the<vfs>().read(url("ships://ship (3).png"))) ) {
                 return false;
diff --git a/samples/sources/sample_02/sample_02.cpp b/samples/sources/sample_02/sample_02.cpp
index 3f953597..7878d72b 100644
--- a/samples/sources/sample_02/sample_02.cpp
+++ b/samples/sources/sample_02/sample_02.cpp
@@ -111,7 +111,7 @@ namespace
             the<vfs>().register_scheme_alias(
                 "ships",
                 url("piratepack://PNG/Retina/Ships"));
-            
+
             image texture_image;
             if ( !images::try_load_image(texture_image, the<vfs>().read(url("ships://ship (3).png"))) ) {
                 return false;
diff --git a/samples/sources/sample_03/sample_03.cpp b/samples/sources/sample_03/sample_03.cpp
index 723995f4..b8b1e396 100644
--- a/samples/sources/sample_03/sample_03.cpp
+++ b/samples/sources/sample_03/sample_03.cpp
@@ -36,6 +36,20 @@ namespace
             if ( k.is_key_pressed(keyboard_key::lsuper) && k.is_key_just_released(keyboard_key::enter) ) {
                 the<window>().toggle_fullscreen(!the<window>().fullscreen());
             }
+
+            if ( k.is_key_just_released(keyboard_key::space) ) {
+                the<profiler>().record_for(std::chrono::seconds(1))
+                .then([](const profiler::recording_info& info){
+                    the<debug>().trace("Profile done: %0", info.events.size());
+                    profilers::try_save_recording_info(info, the<vfs>().write({"desktop", "trace.json"}, false));
+                });
+                the<deferrer>().do_in_main_thread([](){
+                    the<library>().load_asset_async<prefab_asset>("scenes/spine_scene_prefab.json")
+                    .then([](const prefab_asset::load_result& prefab_data){
+                        the<world>().instantiate(prefab_data->content());
+                    });
+                });
+            }
         }
     };
 
diff --git a/samples/sources/sample_05/sample_05.cpp b/samples/sources/sample_05/sample_05.cpp
index 24917718..a963c62d 100644
--- a/samples/sources/sample_05/sample_05.cpp
+++ b/samples/sources/sample_05/sample_05.cpp
@@ -19,7 +19,7 @@ namespace
             the<vfs>().register_scheme_alias(
                 "audio",
                 url("rpgaudio://Audio"));
-            
+
             auto sstream1 = the<audio>().create_stream(the<vfs>().read(url("audio://chop.ogg")));
             auto sstream2 = the<audio>().create_stream(*the<vfs>().load(url("audio://footstep00.ogg")));
 
@@ -29,7 +29,7 @@ namespace
 
             sound_src1_ = the<audio>().create_source(sstream1);
             sound_src2_ = the<audio>().create_source(sstream2);
-            
+
             if ( !sound_src1_ || !sound_src2_ ) {
                 return false;
             }
diff --git a/sources/enduro2d/core/audio_impl/audio_bass.cpp b/sources/enduro2d/core/audio_impl/audio_bass.cpp
index bd83c57b..5af43688 100644
--- a/sources/enduro2d/core/audio_impl/audio_bass.cpp
+++ b/sources/enduro2d/core/audio_impl/audio_bass.cpp
@@ -235,7 +235,7 @@ namespace e2d
         HCHANNEL channel = stream->state().stream()
             ? stream->state().sound()
             : BASS_SampleGetChannel(stream->state().sound(), FALSE);
-            
+
         if ( !channel ) {
             state_->dbg().error("AUDIO: can net retrive sound channel");
             return nullptr;
diff --git a/sources/enduro2d/core/audio_impl/audio_bass_impl.cpp b/sources/enduro2d/core/audio_impl/audio_bass_impl.cpp
index aaa12af2..84916684 100644
--- a/sources/enduro2d/core/audio_impl/audio_bass_impl.cpp
+++ b/sources/enduro2d/core/audio_impl/audio_bass_impl.cpp
@@ -43,7 +43,7 @@ namespace e2d
     const input_stream_uptr& sound_stream::internal_state::stream() const noexcept {
         return stream_;
     }
-    
+
     //
     // sound_source::internal_state
     //
diff --git a/sources/enduro2d/core/dbgui.cpp b/sources/enduro2d/core/dbgui.cpp
index 96737ea4..9d714c78 100644
--- a/sources/enduro2d/core/dbgui.cpp
+++ b/sources/enduro2d/core/dbgui.cpp
@@ -179,7 +179,7 @@ namespace e2d
 
             io.DisplaySize =
                 window_.real_size().cast_to<f32>();
-            
+
             io.DisplayFramebufferScale = io.DisplaySize.x > 0.f && io.DisplaySize.y > 0.f
                 ? window_.framebuffer_size().cast_to<f32>() / v2f(io.DisplaySize)
                 : v2f(1.f, 1.f);
diff --git a/sources/enduro2d/core/engine.cpp b/sources/enduro2d/core/engine.cpp
index 964ea43b..27e207fc 100644
--- a/sources/enduro2d/core/engine.cpp
+++ b/sources/enduro2d/core/engine.cpp
@@ -519,7 +519,7 @@ namespace e2d
                 app->shutdown();
                 throw;
             }
-            
+
             the<input>().frame_tick();
             window::poll_events();
 
diff --git a/sources/enduro2d/core/profiler.cpp b/sources/enduro2d/core/profiler.cpp
index b1e9ce10..b374cfdb 100644
--- a/sources/enduro2d/core/profiler.cpp
+++ b/sources/enduro2d/core/profiler.cpp
@@ -6,7 +6,6 @@
 
 #include <enduro2d/core/profiler.hpp>
 
-#include <enduro2d/core/deferrer.hpp>
 #include <enduro2d/core/engine.hpp>
 #include <enduro2d/core/vfs.hpp>
 
@@ -28,7 +27,7 @@ namespace
 
     str recording_info_to_json(const profiler::recording_info& src) {
         str dst("{\"traceEvents\":[\n");
-        
+
         dst += strings::rformat(
             "  {\"name\":\"thread_name\",\"ph\":\"M\",\"tid\":%0,\"pid\":0,\"args\":{\"name\":\"%1\"}},\n",
             std::hash<std::thread::id>()(the<engine>().main_thread()),
@@ -159,7 +158,7 @@ namespace e2d
             std::move(args),
             std::this_thread::get_id(),
             time::to_chrono(time::now_us())};
-        
+
         std::lock_guard guard(rmutex_);
         for ( const auto& sink : sinks_ ) {
             if ( sink ) {
@@ -175,7 +174,7 @@ namespace e2d
         end_scope_info event{
             std::this_thread::get_id(),
             time::to_chrono(time::now_us())};
-        
+
         std::lock_guard guard(rmutex_);
         for ( const auto& sink : sinks_ ) {
             if ( sink ) {
@@ -194,7 +193,7 @@ namespace e2d
             std::move(args),
             std::this_thread::get_id(),
             time::to_chrono(time::now_us())};
-        
+
         std::lock_guard guard(rmutex_);
         for ( const auto& sink : sinks_ ) {
             if ( sink ) {
@@ -213,7 +212,7 @@ namespace e2d
             std::move(args),
             std::this_thread::get_id(),
             time::to_chrono(time::now_us())};
-        
+
         std::lock_guard guard(rmutex_);
         for ( const auto& sink : sinks_ ) {
             if ( sink ) {
@@ -237,7 +236,7 @@ namespace e2d::profilers
             return false;
         }
     }
-    
+
     bool try_save_recording_info(
         const profiler::recording_info& src,
         const output_stream_uptr& dst) noexcept
diff --git a/sources/enduro2d/core/render_impl/render_none.cpp b/sources/enduro2d/core/render_impl/render_none.cpp
index 666dfd2c..4d10eda5 100644
--- a/sources/enduro2d/core/render_impl/render_none.cpp
+++ b/sources/enduro2d/core/render_impl/render_none.cpp
@@ -245,7 +245,7 @@ namespace e2d
         E2D_UNUSED(command);
         return *this;
     }
-    
+
     render& render::update_buffer(
         const index_buffer_ptr& ibuffer,
         buffer_view indices,
diff --git a/sources/enduro2d/core/render_impl/render_opengl.cpp b/sources/enduro2d/core/render_impl/render_opengl.cpp
index 52d22e83..bbd191e5 100644
--- a/sources/enduro2d/core/render_impl/render_opengl.cpp
+++ b/sources/enduro2d/core/render_impl/render_opengl.cpp
@@ -514,7 +514,7 @@ namespace e2d
         }
 
         gl_shader_id fs(state_->dbg());
-        
+
         {
             E2D_PROFILER_SCOPE("render.compile_fragment_shader");
 
diff --git a/sources/enduro2d/core/vfs.cpp b/sources/enduro2d/core/vfs.cpp
index 15e73bea..ad14b439 100644
--- a/sources/enduro2d/core/vfs.cpp
+++ b/sources/enduro2d/core/vfs.cpp
@@ -179,7 +179,7 @@ namespace e2d
             {"url", url.schemepath()}
         });
         return load_async(url).then([](auto&& src){
-            return std::optional(std::forward<decltype(src)>(src));
+            return std::optional<buffer>(std::forward<decltype(src)>(src));
         }).get_or_default(std::nullopt);
     }
 
@@ -202,7 +202,7 @@ namespace e2d
             {"url", url.schemepath()}
         });
         return load_as_string_async(url).then([](auto&& src){
-            return std::optional(std::forward<decltype(src)>(src));
+            return std::optional<str>(std::forward<decltype(src)>(src));
         }).get_or_default(std::nullopt);
     }
 
diff --git a/sources/enduro2d/high/starter.cpp b/sources/enduro2d/high/starter.cpp
index e2c4f587..54cb288e 100644
--- a/sources/enduro2d/high/starter.cpp
+++ b/sources/enduro2d/high/starter.cpp
@@ -99,7 +99,7 @@ namespace
 
         void frame_render() final {
             E2D_PROFILER_SCOPE("application.frame_render");
-           
+
             world& w = the<world>();
 
             {
diff --git a/sources/enduro2d/high/systems/render_system.cpp b/sources/enduro2d/high/systems/render_system.cpp
index 9c9fc66f..264ee187 100644
--- a/sources/enduro2d/high/systems/render_system.cpp
+++ b/sources/enduro2d/high/systems/render_system.cpp
@@ -26,7 +26,7 @@ namespace
         const auto comp = [](const auto& l, const auto& r) noexcept {
             return std::get<scene>(l).depth() < std::get<scene>(r).depth();
         };
-        
+
         const auto func = [&ctx](
             const ecs::const_entity&,
             const scene&,
@@ -36,7 +36,7 @@ namespace
                 ctx.draw(node);
             });
         };
-        
+
         systems::for_extracted_sorted_components<scene, actor>(
             owner,
             comp,
@@ -50,7 +50,7 @@ namespace
         const auto comp = [](const auto& l, const auto& r) noexcept {
             return std::get<camera>(l).depth() < std::get<camera>(r).depth();
         };
-        
+
         const auto func = [&drawer, &owner](
             const ecs::const_entity&,
             const camera& cam,
@@ -60,7 +60,7 @@ namespace
                 for_all_scenes(ctx, owner);
             });
         };
-        
+
         systems::for_extracted_sorted_components<camera, actor>(
             owner,
             comp,
diff --git a/sources/enduro2d/high/world.cpp b/sources/enduro2d/high/world.cpp
index 4af9bde9..3d8313ce 100644
--- a/sources/enduro2d/high/world.cpp
+++ b/sources/enduro2d/high/world.cpp
@@ -196,7 +196,7 @@ namespace e2d
 
     gobject world::instantiate(const prefab& prefab, const node_iptr& parent) {
         E2D_PROFILER_SCOPE("world.instantiate");
-        
+
         gobject inst = new_instance(*this, prefab);
 
         if ( parent ) {