Under what circumstances can ExecutionContext.Capture() return null?

[sakno]

... because the following code requires to check the context on null before calling Restore:

ExecutionContext? current = ExecutionContext.Capture(); // nullable
ExecutionContext.Restore(myContext);
try
{
  // do some stuff inside of myContext
}
finally
{
   if (current is not null) ExecutionContext.Restore(current); // Restore expects that the argument is not null
}

[sakno]

Oh, I see:

runtime/src/libraries/System.Private.CoreLib/src/System/Threading/ExecutionContext.cs

Lines 55 to 68 in 94bec76

	public static ExecutionContext? Capture()
	{
	ExecutionContext? executionContext = Thread.CurrentThread._executionContext;
	if (executionContext == null)
	{
	executionContext = Default;
	}
	else if (executionContext.m_isFlowSuppressed)
	{
	executionContext = null;
	}
	return executionContext;
	}

If flow is suppressed, then context is null.