[feat] Need to optimized with async prefetch.

nanovllm/utils/context.py

@@ -32,6 +32,8 @@ class Context:
     # Starting position within block where decode tokens began (for accumulated token tracking)
     # Used when batching decode offloads - we need to attend to all accumulated tokens
     decode_start_pos_in_block: int = 0
+    # Current chunk index for ring buffer pipeline (prefill only)
+    current_chunk_idx: int = 0
 
 
 _CONTEXT = Context()
@@ -57,6 +59,7 @@ def set_context(
     chunked_seq=None,
     decode_pos_in_block=0,
     decode_start_pos_in_block=0,
+    current_chunk_idx=0,
 ):
     global _CONTEXT
     _CONTEXT = Context(
@@ -75,6 +78,7 @@ def set_context(
         chunked_seq=chunked_seq,
         decode_pos_in_block=decode_pos_in_block,
         decode_start_pos_in_block=decode_start_pos_in_block,
+        current_chunk_idx=current_chunk_idx,
     )