faster tostring
faster tostring

from 16 -> 15 sec (10 million messages). 6~7%

tetrodoxin/NLog,luigiberrettini/NLog,tohosnet/NLog,BrutalCode/NLog,bjornbouetsmith/NLog,hubo0831/NLog,bryjamus/NLog,luigiberrettini/NLog,MoaidHathot/NLog,michaeljbaird/NLog,MartinTherriault/NLog,littlesmilelove/NLog,bjornbouetsmith/NLog,AndreGleichner/NLog,ie-zero/NLog,kevindaub/NLog,UgurAldanmaz/NLog,bhaeussermann/NLog,bhaeussermann/NLog,UgurAldanmaz/NLog,breyed/NLog,ie-zero/NLog,tohosnet/NLog,NLog/NLog,AndreGleichner/NLog,littlesmilelove/NLog,tetrodoxin/NLog,MartinTherriault/NLog,kevindaub/NLog,ilya-g/NLog,hubo0831/NLog,304NotModified/NLog,bryjamus/NLog,michaeljbaird/NLog,MoaidHathot/NLog,BrutalCode/NLog,breyed/NLog,nazim9214/NLog,snakefoot/NLog,ilya-g/NLog,nazim9214/NLog,sean-gilliam/NLog