fileType := reflect.TypeFor[*os.File]()
	bufferType := reflect.TypeFor[*bytes.Buffer]()

	nBytes := int64(1 << 10)
	newFileFunc := func() (r io.Reader, done func(), err error) {
		f, err := os.CreateTemp("", "net-http-newfilefunc")
		if err != nil {
			return nil, nil, err
		}

		// Write some bytes to the file to enable reading.

	}{
		{
			name:             "file, length",
			readerFunc:       newFileFunc,
			contentLength:    nBytes,
			expectedReadFrom: true,
		},
		{
			name:       "file, no length",
			readerFunc: newFileFunc,
		},
		{
			name:          "file, negative length",
			readerFunc:    newFileFunc,
			contentLength: -1,
		},
		{
			name:          "buffer",