* subtypes,handlers: add runtime trace regions
The subtype.Filterable and handlers.ProtoToStruct functions
are costly and worth measuring whenever runtime tracing
is in use. This has almost no cost when tracing is not in use,
so there's little harm in having them in place.
* testing: Add TRACING.md
TRACING.md contains information about how to perform
Go runtime tracing of the Boundary application.
Johan Brandhorst-Satzkorn
a89573b35f