public ValueTask <ImmutableArray <ActiveStatementTrackingSpan> > GetAdjustedTrackingSpansAsync(
     Document document,
     ITextSnapshot snapshot,
     CancellationToken cancellationToken
     ) =>
 _session?.GetAdjustedTrackingSpansAsync(document, snapshot, cancellationToken)
 ?? new(ImmutableArray <ActiveStatementTrackingSpan> .Empty);
 public Task <ImmutableArray <ActiveStatementTrackingSpan> > GetAdjustedTrackingSpansAsync(Document document, ITextSnapshot snapshot, CancellationToken cancellationToken)
 => _session?.GetAdjustedTrackingSpansAsync(document, snapshot, cancellationToken) ?? SpecializedTasks.EmptyImmutableArray <ActiveStatementTrackingSpan>();