metadata = make(map[string]string)

	for _, hdr := range mimesHeader {
		// Extract all query values.
		err = extractMetadataFromMime(ctx, hdr, metadata)
		if err != nil {
			return nil, err
		}
	}

	// Set content-type to default value if it is not set.
	if _, ok := metadata[strings.ToLower(xhttp.ContentType)]; !ok {

			metadata:   nil,
			shouldFail: true,
		},
	}

	// Validate if the extracting headers.
	for i, testCase := range testCases {
		metadata := make(map[string]string)
		err := extractMetadataFromMime(context.Background(), textproto.MIMEHeader(testCase.header), metadata)
		if err != nil && !testCase.shouldFail {
			t.Fatalf("Test %d failed to extract metadata: %v", i+1, err)
		}

			hashReader.SetExpectedMax(lengthRange.Max)
		}
	}

	// Extract metadata to be saved from received Form.
	metadata := make(map[string]string)
	err = extractMetadataFromMime(ctx, textproto.MIMEHeader(formValues), metadata)
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	rawReader := hashReader