what is bust limit in Juniper?

I am checking rate limit configuration on one of the juniper router

policer vpnabcd-500000k {

filter-specific;

if-exceeding {

bandwidth-limit 500m;

burst-size-limit 10m;

}

then discard;

What is burst-size-limit here? Will I get 510Mb speed? or I will be able to send just 10 MB size data once I cross 500 MB?