Change to 3.10 and provided detailed description about event queue usage

Author: pstephengoogle

pyproject.toml

@@ -5,7 +5,7 @@ description = "A2A Python SDK"
 readme = "README.md"
 license = { file = "LICENSE" }
 authors = [{ name = "Google LLC", email = "[email protected]" }]
-requires-python = ">=3.12"
+requires-python = ">=3.10"
 keywords = ["A2A", "A2A SDK", "A2A Protocol", "Agent2Agent"]
 dependencies = [
     "httpx>=0.28.1",
@@ -22,7 +22,7 @@ classifiers = [
   "Intended Audience :: Developers",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",
-  "Programming Language :: Python :: 3.12",
+  "Programming Language :: Python :: 3.10",
   "Operating System :: OS Independent",
   "Topic :: Software Development :: Libraries :: Python Modules",
   "License :: OSI Approved :: Apache Software License",

src/a2a/server/events/event_queue.py

@@ -61,6 +61,20 @@ def enqueue_event(self, event: Event):
     async def dequeue_event(self, no_wait: bool = False) -> Event:
         """Dequeues an event from the queue.
 
+        This implementation expects that dequeue to raise an exception when
+        the queue has been closed. In python 3.13+ this is naturally provided
+        by the QueueShutDown exception generated when the queue has closed and
+        the user is awaiting the queue.get method. Python<=3.12 this needs to
+        manage this lifecylce itself. The current implementation can lead to
+        blocking if the dequeue_event is called before the EventQueue has been
+        closed but when there are no events on the queue. Two ways to avoid this
+        are to call this with no_wait = True which won't block, but is the
+        callers responsibility to retry as appropriate. Alternatively, one can
+        use a async Task management solution to cancel the get task if the queue
+        has closed or some other condition is met. The implementation of the
+        EventConsumer uses an async.wait with a timeout to abort the
+        dequeue_event call and retry, when it will return with a closed error.
+
         Args:
             no_wait: If True, retrieve an event immediately or raise `asyncio.QueueEmpty`.
                      If False (default), wait until an event is available.