Hi @fk22, If you are just getting started in using the eye tracker and the EyeX SDK then I suggest you may find it simpler to get up and running with the new Tobii Core SDK which not only contain a number of different samples which may be useful to you, but also provides support for the NuGet package installer to make running your first samples quickly.
You can find further information online @ https://tobii.github.io/CoreSDK/articles/getting_started.html
There is no function straight out of the box that logs the number of blinks during tracking however you do of course have access to the Gaze data stream and could measure period for which no tracking was recorded.. however you would need to consider this might also be as a result of the user looking away from the screen or environmental factors. A degree of of filtering based upon duration of data loss would be necessary.
However, please bear in mind that if you intended to store the gaze data for analytic or scientific usage, this would again necessitate the acquisition of a special Tobii Pro licence to do so.