##Vertical space and text
##vertical space text
##Use '|||' to add some vertical space ('nudge' for less space) or just type a colon-label to add text.
C: Client;
S: Server;
B: Backend;
->C: Hit;
C=>S: Request;
S>>B: Query;
: the backend is very busy here;
S<<B: Response;
C<=S: Reply;
|||;
C->S [weak]: Next Request;

