protected override Task <ImmutableArray <DiagnosticData> > GetDiagnosticsAsync(
RequestContext context, Document document, DiagnosticMode diagnosticMode, CancellationToken cancellationToken)
{
// For closed files, go to the IDiagnosticService for results. These won't necessarily be totally up to
// date. However, that's fine as these are closed files and won't be in the process of being edited. So
// any deviations in the spans of diagnostics shouldn't be impactful for the user.
return(DiagnosticService.GetPullDiagnosticsAsync(document, includeSuppressedDiagnostics: false, diagnosticMode, cancellationToken).AsTask());
}