fix(python): [1/3] improve in-memory size estimation for queue items

amber/src/main/python/core/util/customized_queue/linked_blocking_multi_queue.py

@@ -29,13 +29,34 @@
 T = TypeVar("T")
 
 
+def _estimate_in_mem_size(item: T) -> int:
+    """
+    Estimate in-memory bytes for queue accounting.
+    Prefer payload/frame byte size when available; otherwise fall back to object size.
+    """
+    if item is None:
+        return 0
+
+    payload = getattr(item, "payload", None)
+    frame = getattr(payload, "frame", None) if payload is not None else None
+    if frame is not None:
+        if hasattr(frame, "nbytes"):
+            return int(frame.nbytes)
+        if hasattr(frame, "to_table"):
+            table = frame.to_table()
+            if hasattr(table, "nbytes"):
+                return int(table.nbytes)
+
+    return sys.getsizeof(item)
+
+
 class LinkedBlockingMultiQueue(IKeyedQueue):
     @inner
     class Node(Generic[T]):
         def __init__(self, item: T):
             self.item = item
             self.next: Optional[LinkedBlockingMultiQueue.Node[T]] = None
-            self.in_mem_size = sys.getsizeof(item)
+            self.in_mem_size = _estimate_in_mem_size(item)
 
     @inner
     class SubQueue(Generic[T]):