Instrument without a block?

[rmosolgo]

Hi! I'm working on improving the Scout integration for GraphQL-Ruby. My library sometimes spins up new Fibers, runs them for a while, then pauses them ... then resumes them again. I'd like a way to report the duration while the Fiber is running, but not while it's paused. I think the best approach here is to make two separate spans: one before the pause and one after it.

However, the catch is, the library doesn't know when (or where in the code) the Fiber will be paused. I can't wrap the before-part in a do ... end block -- instead, code runs ... then eventually it may yield. So I'm looking for a way to start a new span, then manually finish it when I observe that Fiber pause. Is there a supported way to do this?

For now, I'm going to use the internal implementation from .implement:

scout_apm_ruby/lib/scout_apm/tracer.rb

Lines 24 to 39 in eebbc5f

	def self.instrument(type, name, options={}) # Takes a block
	layer = ScoutApm::Layer.new(type, name)
	layer.desc = options[:desc] if options[:desc]
	layer.subscopable! if options[:scope]
	req = ScoutApm::RequestManager.lookup
	req.start_layer(layer)
	req.ignore_children! if options[:ignore_children]
	begin
	yield
	ensure
	req.acknowledge_children! if options[:ignore_children]
	req.stop_layer
	end
	end

Basically I'll separate those two parts -- before yield and after it -- and call them as needed. But if there's a better way, I'd like to use it! Thanks.