Switch from gRPC message-based instrumentation to transaction-based (streaming)

[luke-sterkowicz]

Is your feature request related to a problem? Please describe.

We have an endpoint where we return streamed gRPC responses. Turns out there's a separate span created for each message in the stream which leads to sometimes enormous span payloads that depend on the number of streamed results in a short time frame.

Describe the solution you'd like

While there may be reasonable use cases for instrumenting each gRPC response, there should also be a mode where we instrument the gRPC call/transaction as a whole. My request is to add such mode, to be configured by some switch.

Describe alternatives you've considered

No response

Additional context

No response

[breedx-splk]

I'm not entirely sure if there's a spec around this, but I've also heard folks ask for a span attribute to summarize the number of response messages that were streamed. Could be a helpful addition to this.