Test Run Results Request JSON Payload - Attach document

How does one record test run results that includes attachment(s) such as images and other document types? Currently one has to make 2 separate API requests to achieve this outcome. 

E.g.

1. https://science37.spiraservice.net/services/v5_0/RestService.svc/projects/%7Bproject_id%7D/test-runs/record
2. https://api.inflectra.com/Spira/Services/v5_0/RestService.svc/projects/%7Bproject_id%7D/documents/file?filename={filename}&tags={tags}&folder_id={folder_id}&document_type_id={document_type_id}&artifact_type_id={artifact_type_id}&artifact_id={artifact_id}

I wish to make use of a single request payload to record test run results and attach documents for the same test run.