toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (height != null) 'height': height!,
if (kind != null) 'kind': kind!,
if (mimeType != null) 'mime_type': mimeType!,
if (url != null) 'url': url!,
if (width != null) 'width': width!,
};