Handle empty queue after K_CF_RUN_LOOP_RUN_HANDLED_SOURCE

Occassionally CFRunLoopInMode() returns K_CF_RUN_LOOP_RUN_HANDLED_SOURCE
even though the _hid_read_callback() has not been invoked, resulting
in reading from an empty queue. We can handle this by re-running the run
loop with a retry mechanism.

fido2/hid/macos.py

@@ -253,14 +253,28 @@ def _dev_read_thread(hid_device):
         hid_device.handle, REMOVAL_CALLBACK, ctypes.py_object(hid_device)
     )
 
-    # Run the run loop
-    run_loop_run_result = cf.CFRunLoopRunInMode(
-        K_CF_RUNLOOP_DEFAULT_MODE, 4, True  # Timeout in seconds
-    )  # Return after source handled
-
-    # log any unexpected run loop exit
-    if run_loop_run_result != K_CF_RUN_LOOP_RUN_HANDLED_SOURCE:
-        logger.error("Unexpected run loop exit code: %d", run_loop_run_result)
+    max_retries = 2  # Maximum number of run loop retries
+    retries = 0
+
+    while retries < max_retries:
+        # Run the run loop
+        run_loop_run_result = cf.CFRunLoopRunInMode(
+            K_CF_RUNLOOP_DEFAULT_MODE, 4, True  # Timeout in seconds
+        )  # Return after source handled
+
+        received_data = not hid_device.read_queue.empty()
+        if run_loop_run_result == K_CF_RUN_LOOP_RUN_HANDLED_SOURCE:
+            if received_data:
+                # Return when data has been received
+                break
+            else:
+                # Retry running the run loop if data has not been received yet
+                logger.debug("Read queue empty after HANDLE_SOURCE, attempting retry")
+                retries += 1
+        else:
+            # log any unexpected run loop exit
+            logger.error("Unexpected run loop exit code: %d", run_loop_run_result)
+            break
 
     # Unschedule from run loop
     iokit.IOHIDDeviceUnscheduleFromRunLoop(