Is there a way to globally set some Activity as a parent in case an Activity is ever created without a parent?

[thecristidima]

Let's say we have a library that among other things exposes an ActivitySource and users use it to create Activities. We're trying to find a way to be able to always have a parent for activities created without a parent.

A very basic example:

MyLib.Initialize(defaultParent);
Activity.Current = null; // simulate user creating an Activity in another thread perhaps
var activity = MyLib.ActivitySource.StartActivity("NoParent"); // activity.Parent is defaultParent

What we tried is creating an ActivityListener and on the Sample method we set Activity.Current = defaultParent which seems to work until we actually use OpenTelemetry (unclear why, but it feels hacky anyway).

Is there a way to actually make this happen? My gut feeling is no or at least not without a seriously hacky way, but the idea of having a default parent sounds like something that should work.