Added a flushg during sampling to prevent spikes on low vram qwen

extensions_built_in/diffusion_models/qwen_image/qwen_image.py

@@ -210,6 +210,17 @@ class QwenImageModel(BaseModel):
                 control_img = control_img.resize(
                     (gen_config.width, gen_config.height), Image.BILINEAR
                 )
+        
+        # flush for low vram if we are doing that
+        flush_between_steps = self.model_config.low_vram
+            # Fix a bug in diffusers/torch
+        def callback_on_step_end(pipe, i, t, callback_kwargs):
+            if flush_between_steps:
+                flush()
+            latents = callback_kwargs["latents"]
+            
+            return {"latents": latents}
+        
         sc = self.get_bucket_divisibility()
         gen_config.width = int(gen_config.width  // sc * sc)
         gen_config.height = int(gen_config.height // sc * sc)
@@ -224,6 +235,7 @@ class QwenImageModel(BaseModel):
             true_cfg_scale=gen_config.guidance_scale,
             latents=gen_config.latents,
             generator=generator,
+            callback_on_step_end=callback_on_step_end,
             **extra
         ).images[0]
         return img