Improve filtering out middle span by SpanExportingPredicate

[quaff]

If we have spans like

A > 
   B > 
       C

1. with leaf span C dropped, It's expected that spans will be

A > 
   B

2. with root span A dropped, It's expected that spans will be

B > 
   C

but a warning show up that span B has invalid parent span

3. with middle span B dropped, we expect

A > 
   C

but got

A
C

and warning show up that span C has invalid parent span
warning by jaeger: invalid parent span IDs=c6ababd1d88b00b1; skipping clock skew adjustment.

Could we reset children's parent span id to fix such skew?

[jonatan-ivanov]

For the sake of documentation, I think these are related:

• Introduce withParentOnly for @Observed micrometer#3843
• Provide a way to make decisions based on the parent in ObservationPredicate micrometer#3678

Could you please tell us how you "drop" spans?
Are you using an ObservationPredicate or a SpanExportingPredicate or a SpanHandler or something else?

[quaff]

For the sake of documentation, I think these are related:

• Introduce withParentOnly for @Observed micrometer#3843
• Provide a simple way to make decisions based on the parent in ObservationPredicate micrometer#3678

Could you please tell us how you "drop" spans? Are you using an ObservationPredicate or a SpanExportingPredicate or a SpanHandler or something else?

For example I want to drop connection but want to keep it's descendants.

	@Bean
	SpanExportingPredicate noConnectionSpanExportingPredicate() {
		return span -> !span.getName().equals("connection");
	}

Sometime I want to drop connection and it's descendants, hopeful both cases are supported.