How to annotate controller method that returns different content types of responses

I've a controller to download a file which can return either application/zip content type or application/json in case of any error. I'm trying to annotate controller to produce the correct swagger.json

[HttpGet("download/{id}")]
[ProducesResponseType(typeof(FileStreamResult), StatusCodes.Status200OK)]
[ProducesResponseType(typeof(FileStreamResult), StatusCodes.Status206PartialContent)]
[ProducesResponseType(typeof(ErrorResponse), StatusCodes.Status404NotFound)]
[ProducesResponseType(typeof(ErrorResponse), StatusCodes.Status416RangeNotSatisfiable)]
[Produces(MediaTypeNames.Application.Zip)]
public ActionResult Download(Guid id)
{
}

But in this case the swagger.json will contain responses like below:

"responses": {
      "200": {
        "description": "Returns the content of the file",
        "content": {
          "application/zip": {
            "schema": {
              "type": "string",
              "format": "binary"
            }
          }
        }
      },
      "206": {
        "description": "Supports range requests",
        "content": {
          "application/zip": {
            "schema": {
              "type": "string",
              "format": "binary"
            }
          }
        }
      },
      "404": {
        "description": "The file was not found",
        "content": {
          "application/zip": {
            "schema": {
              "$ref": "#/components/schemas/ErrorResponse"
            }
          }
        }
      },
      "416": {
        "description": "The range is not satisfiable",
        "content": {
          "application/zip": {
            "schema": {
              "$ref": "#/components/schemas/ErrorResponse"
            }
          }
        }
      }
    }
  }

But I would like define content type application/json for 404 and 416. Is there any way how to achieve this?

Desired state:

      "404": {
        "description": "The file was not found",
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/ErrorResponse"
            }
          }
        }
      },
      "416": {
        "description": "The range is not satisfiable",
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/ErrorResponse"
            }
          }
        }
      }

• First, remove the [Produces(MediaTypeNames.Application.Zip)] attribute because that sets a Content-Type for all other defined responses.
• For client-error 400-499 responses (as opposed to internal-server-error 500-599 responses) we're ostensibly meant to use the [ProducesErrorResponseType] attribute, but it lacks a constructor overload for specifying exact HTTP status-codes and Content-Type values.
• Fortunately we can just use [ProducesResponseType] for everything, including client-errors, but use a different ctor overload:
  • The ProducesResponseTypeAttribute(Type, Int32, String, params String[]) ctor lets you specify the C# DTO Type, the HTTP status code, and Content-Type (the trailing params String[] parameter is for "additional content-types" which I honestly have no idea about, but we can safely ignore it).
  • There is one catch, though: certain versions of Swashbuckle and ASP.NET Core (around v6.0) ignored the Content-Type set using \[ProducesContentType\]. _{I believe it's fixed now, but let me know if it doesn't work and I'll update my answer.}

Try this:

// For brevity:
using static Microsoft.AspNetCore.Http.StatusCodes;
using Mime = MediaTypeNames.Application;

[HttpGet("download/{id}")]
[ProducesResponseType( typeof(FileStreamResult), Status200OK                 , Mime.Zip  )]
[ProducesResponseType( typeof(FileStreamResult), Status206PartialContent     , Mime.Zip  )]
[ProducesResponseType( typeof(ErrorResponse)   , Status404NotFound           , Mime.Json )]
[ProducesResponseType( typeof(ErrorResponse)   , Status416RangeNotSatisfiable, Mime.Json )]
public async Task<ActionResult> Download( Guid id, CancellationToken cancellationToken )
{
    throw new NotImplementedException();
}