Hi, I'm wondering if there's a configuration option that I'm missing from the docs for adding sample rates for OpenTracing headers to requests. Right now it seems all requests are sampled and thats not what we want exactly.

I've read this schema for the config file but I don't see anything related to what I'm curious about: https://github.com/envoyproxy/envoy/blob/master/source/common/json/config_schemas.cc