Brave http client instrumentation allow users to inject a sampler at client level and it would be great to include something similar here. Currently we only have RequestSampler for server middleware but the same interface could perfectly work for the client middleware.

The use case is a request that is not sampled by default (maybe internal endpoint) but you might want to trace a specific request to other service. My use case is that I do sampling 33% but I want to trace 100% requests to a payment endpoint and right now I don't have means to make the payment endpoint to be traced 100% as my sampling policy is global (and it is a monolith with LOTS of endpoints).

Ping @adriancole @basvanbeek