A new process is created by an existing process by forking.  The fork
operation clones the process executing it.  The original and cloned
processes (including address spaces) are identical except for some
small things, the most important of which is that the child has a
return value of 0 from the fork operation; the parent has a return
value of the child's pid.

fork_example shows basic forking.  We use sleep() to mimic doing some
work that takes some time.  When the child wakes up, it terminates.
Because the parent has not yet join'ed to the child (and the child hasn't
been detached), the child becomes a "zombie" -- a terminated process that
hasn't been eliminated from the system, pending a join by the parent.

forklatency measures how long fork takes on your system.