Fix multiprocessing.event to match the new threading.Event API
diff --git a/Lib/multiprocessing/synchronize.py b/Lib/multiprocessing/synchronize.py
index dacf45a..716f3c7 100644
--- a/Lib/multiprocessing/synchronize.py
+++ b/Lib/multiprocessing/synchronize.py
@@ -301,5 +301,10 @@
                 self._flag.release()
             else:
                 self._cond.wait(timeout)
+
+            if self._flag.acquire(False):
+                self._flag.release()
+                return True
+            return False
         finally:
             self._cond.release()