Multipart file upload not supported (Django Rest Framework use case)

### Multipart file upload not supported (Django Rest Framework use case)

**Description**  
Unable to upload files using SDK in DRF-based APIs.

**Code snippet**

    files = {"file": open("test.pdf", "rb")}

    response = client.request(
        "POST",
        base_url,
        "/upload",
        data=files
    )

**Issue**  
No support for multipart/form-data encoding.