client unexpectedly lost persistent connection

When the client set timeouts using following API:

    evhttp_connection_set_connect_timeout_tv(...);
    evhttp_connection_set_write_timeout_tv(...);
    evhttp_connection_set_read_timeout_tv(...);

Seems libevent does not stop EV_READ/EV_WRITE timer after last request done. It cause idle connection drop unexpectedly if last request done and no new request send out within timeout periods.