/*
 * Get the next event from the event queue, or block until an event is
 * available.
 *
 * Aliases:
 *   Fam::Connection#next_ev
 *   Fam::Connection#ev
 *
 * Examples:
 *   ev = fam.next_event
 *
 */
static VALUE fam_conn_next_ev(VALUE self) {