[FEA] Performance Critical markers

[ryanolson]

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

SRF is comprised of code that constructs and initializes a runtime and code the executes the a pipeline within the confines of the runtime.

It would be nice to have a system in place that clearly marks particular sections of the code which are performance critical, i.e. will be evaluated in the "hot path" and may effect the performance of an executing pipeline.

This would be valuable information for both developers and reviewers.

Describe the solution you'd like

Not sure.

Additional context
Add any other context, code examples, or references to existing implementations about the feature request here.