- Changed `BurnPdfCommand` from empty class to a `record` with properties: `SourceBuffer`, `InstantJSONList`, `EnvelopeId`. - Updated `BurnPdfCommandHandler` to implement `IRequestHandler<BurnPdfCommand, byte[]>`. - Modified `Handle` method to be async and use the `request` data to return PDF bytes. - Removed obsolete `BurnPdfCommand` class and updated related logic accordingly.