I have set highlight color as white color below is the code in swift. But the hightlight text becomes black color text when highlighted rest other annotation underline and strikeout those colour are white and working properly.
let white:UInt32 = 0x22222222
//Highlight color setting
plugin.setColor(Int32(bitPattern:white), forFeature: 4)
//Underline color setting
plugin.setColor(Int32(bitPattern:white), forFeature: 2)
Underline is properly working while hightlight color is not working i have attached the document as well