In some application, if there are many VRF tables in vpp, and there is external router redundancy, e.g. active-standby. when active router is down, so need to delete route from each VRF table, and add new route to each VRF tables. 

in an application, there are 800 VRFs, with a busy vpp (high traffic), it takes 3 minutes to finish deletion one route from each VRF. as a comparison, using a bulk API (put multiple routes in a single API, in the test, put 100 routes in a API, called 8 times, 800 routes deletion in total), it takes ~2 seconds under same traffic condition.

a bulk API example:
```
define bulk_ip_route_add_del

{     u32 client_index;     u32 context;     u8 is_add;     u8 is_multipath;     u32 n_routes;     vl_api_ip_route_t route[n_routes]; }

;
```
without this API, user need to implement it in vpp plugin and call fib_api_route_add_del after decode the route in the array. and user need to copy ip.api and fib_types.api to their plugin workspace. 

This is a desired new API, for some applications which need many VRFs.