fab Option Color
The color of the FabOption, as an integer in the form 0xAARRGGBB.
If using an XML resource color value, retrieve it in the correct form by calling: ContextCompat.getColor(context, R.color.name_of_color_resource).
Default value is the colorAccent value defined in your app theme (styles.xml). If colorAccent is not defined in your app theme, colorSecondary may be used.
Usage of this property is preferred over the inherited setBackgroundColor and backgroundTintList methods.