MethodTracer: allow trace creation + force trace creation #5323
Description
Safety and defensiveness.
It's very easy and quite common for Ruby scripts to include bits from other places that belong to full-fledged apps. This would then generate an swarm of spurious, unattached, confusing spans out of nowhere at best, or a swarm of logs that a script can't send spans to a nonexistent agent at worst.
Plus it's easier to relax this behaviour later than to tighten it up while people started depending on it.
Note about an idea: this functionality could be gated by an argument kind of like the "no parent" argument Java has. This way generating such traces outside of the usual app scope is an voluntary choice explicitly made by the user.
But maybe see #5294 (comment) regarding discussing these features.
Originally posted by @lloeki in #5294 (comment)