module Sentry::Net::HTTP

def request(req, body = nil, &block)

So we're only instrumenting request when `Net::HTTP` is already started

```
end
# .....
end
}
return request(req, body, &block) # <- request will be called for the second time from the first call
req['connection'] ||= 'close'
start {
unless started?
def request(req, body = nil, &block)
```

Here's part of its definition. As you can see, it usually calls itself inside a #start block
To explain how the entire thing works, we need to know how the original Net::HTTP#request works 
def request(req, body = nil, &block)
  return super unless started? && Sentry.initialized?
  return super if from_sentry_sdk?
  Sentry.with_child_span(op: OP_NAME, start_timestamp: Sentry.utc_now.to_f) do |sentry_span|
    set_sentry_trace_header(req, sentry_span)
    super.tap do |res|
      record_sentry_breadcrumb(req, res)
      if sentry_span
        request_info = extract_request_info(req)
        sentry_span.set_description("#{request_info[:method]} #{request_info[:url]}")
        sentry_span.set_data('url', request_info[:url])
        sentry_span.set_data('http.method', request_info[:method])
        sentry_span.set_data('http.query', request_info[:query]) if request_info[:query]
        sentry_span.set_data('status', res.code.to_i)
      end
    end
  end
end