Backendless.ServerCode.enablePromises()
Backendless.ServerCode.Persistence.beforeCreate('venues_table', function(req) {

    //after calling enablePromises, all asynchronous operations now return a Promise which
    //is very convenient in our case, because we may return it to the CodeRunner
    return Backendless.Counters.of( "venue_counter" ).incrementAndGet().then(
        counter => {
            console.log( "[ASYNC] counter value is - " + counter );

            req.item.venue_id = counter
        },
        error => {
            console.log( "error - " + error.message );

            //throwing the error will interrupt venues-table record creation
            //throw e
        }
    );

});