Python 3.14 (Runtime): Adjust code base about Python 3.14 syntax

AttributeError: 'OrderedSet' object has no attribute 'copy'

Author: amotl

streamz/orderedweakset.py

@@ -26,6 +26,9 @@ def add(self, value):
     def discard(self, value):
         self._od.pop(value, None)
 
+    def copy(self):
+        return OrderedSet(self._od.copy())
+
 
 class OrderedWeakrefSet(weakref.WeakSet):
     def __init__(self, values=()):