Fix bug on kqueue-based platforms, where reactor read operations that
return false from their perform() function are not correctly
re-registered with kqueue.

asio/include/asio/detail/impl/kqueue_reactor.ipp

diff --git a/asio/include/asio/detail/impl/kqueue_reactor.ipp b/asio/include/asio/detail/impl/kqueue_reactor.ipp
index 8db77cb..00ebfeb 100644
--- a/asio/include/asio/detail/impl/kqueue_reactor.ipp
+++ b/asio/include/asio/detail/impl/kqueue_reactor.ipp
@@ -301,12 +301,14 @@
               EV_ADD | EV_ONESHOT, EV_OOBAND, 0, descriptor_data);
         else
           continue;
+        break;
       case EVFILT_WRITE:
         if (!descriptor_data->op_queue_[write_op].empty())
           ASIO_KQUEUE_EV_SET(&event, descriptor, EVFILT_WRITE,
               EV_ADD | EV_ONESHOT, 0, 0, descriptor_data);
         else
           continue;
+        break;
       default:
         break;
       }