Description

ActivityTraceFlags can be updated after activity is started. However, doing so does not update the activity Id.

Reproduction Steps

var activity = new Activity("Test");
activity.Start();
Console.WriteLine("ActivityId Before TraceFlags are set: " + activity.Id);
Console.WriteLine("ActivityTraceFlags Before: " + activity.ActivityTraceFlags);
activity.ActivityTraceFlags |= ActivityTraceFlags.Recorded;
Console.WriteLine("ActivityId After TraceFlags are set: " + activity.Id);
Console.WriteLine("ActivityTraceFlags After: " + activity.ActivityTraceFlags);

---- sample output ----
ActivityId Before TraceFlags are set: 00-b33ee4ebf1fa3d81e0ab30363fe291e2-40f3aace946db1d2-00
ActivityTraceFlags Before: None
ActivityId After TraceFlags are set: 00-b33ee4ebf1fa3d81e0ab30363fe291e2-40f3aace946db1d2-00
ActivityTraceFlags After: Recorded

Expected behavior

Updated ActivityTraceFlags is reflected in Activity.Id

Actual behavior

Updated ActivityTraceFlags is not reflected in Activity.Id

Regression?

No

Known Workarounds

No response

Configuration

No response

Other information

No response