if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	etag := getDecryptedETag(formValues, objInfo, false)

	// We must not use the http.Header().Set method here because some (broken)
	// clients expect the ETag header key to be literally "ETag" - not "Etag" (case-sensitive).
	// Therefore, we have to set the ETag directly as map entry.

	}
}

// An onlyReader only implements io.Reader, no matter what other methods the underlying implementation may have.
type onlyReader struct {
	io.Reader
}

// An onlyWriter only implements io.Writer, no matter what other methods the underlying implementation may have.
type onlyWriter struct {
	io.Writer
}