/*
 * Monitor a file.
 *
 * Returns a Fam::Request object, which is used to identify the monitor
 * associated with events.
 *
 * Aliases:
 *   Fam::Connection#file
 *
 * Examples:
 *   req = fam.monitor_file '/var/log/messages'
 *
 */
static VALUE fam_conn_file(VALUE self, VALUE file) {