activate method
Make a Span instance active.
Span that should become the active Span
When finishSpanOnClose
is true, the span
will automatically be
finished when Scope.close() is called.
Returns a Scope instance to control the end of the active period for the
Span. It is a programming error to neglect calling Scope.close() on
the returned instance.
Implementation
@override
Scope? activate(Span span, bool finishSpanOnClose) {
_scope = NoopScope(span: span);
return active;
}