Combine multiple ruby requests into one pprof file

[Rperry2174]

Right now when using the ruby gem multiple tags are sent in multiple requests, but we should combine them into one (ideally pprof).

@petethepig will provide more info here later

[petethepig]

Some helpful tips on pprof:

We have docs on how to ingest pprof into pyroscope here.

Relations Diagram

pprof is basically a protobuf schema

• 1 profile has multiple samples
• each sample references a location and links it to labels (labels = tags)
• each location is a collection of lines
• each line links to a function and has a line number
• each function has multiple strings such as name, filename, etc
• all strings are encoded in a strings_table and referenced in other places via integers

---

You can see the pprof structure in json format using this tool from our main repo (figured it might be useful for debugging):

cat pkg/convert/testdata/cpu.pprof | go run scripts/pprof-view/main.go

Here's what the output looks like: https://gist.github.com/petethepig/e41226414e3f54a7c0eedb24c5a334da

[korniltsev]

implemented in https://github.com/pyroscope-io/pyroscope-rs/pull/60