Adriana Schwinghammer is about to retire from a job where her sole reward is the gratification of a job well done. 
     And she’s been at it – as a volunteer at Miami Lakes K-8 Center  – for two decades. 
     Schwinghammer, 52, of Miami Lakes -- the mother of Broderick, 25, Chloe, 22, and Aiden, 14, with her husband Sean Schwinghammer – has...