##Hiding and showing entities
##hide show entity turn later
##Use the 'show' and 'hide' keywords to turn entity lines on or off. When defined as hidden, the entity only appears later.
C: Client;
S: Server\n\-(Frontend);
hide B: Backend;
->C: Hit;
C=>S: Request;
show B;
S>>B: Query;
S<<B: Response;
hide B;
C<=S: Reply;
