Creates icon data.
Rarely used directly. Instead, consider using one of the predefined icons like the Icons collection.
The fontPackage argument must be non-null when using a font family that is included in a package. This is used when selecting the font.
Instantiating non-const instances of this class in your app will mean the app cannot be built in release mode with icon tree-shaking (it need to be explicitly opted out at build time). See staticIconProvider for more context.
this.matchTextDirection = false,