timing [mode [args]]
if no mode is given, just reports the current mode.
available timing modes:
	random
	uniform [delay]
	after
Random mode uses a heavy-tailed distribution random-variable for delay, *except* where a delay is marked with [after=0].
Uniform mode ignores all after-delay annotations and uses a fixed delay for all events, which can be used to count transitions.
After mode uses fixed after-annotated delays for timing, and assumes default delays where none are given.
Use 'seed48' to set a random number seed.
timing: uniform (10)
	0	a : 1
	10	b : 0	[by a:=1]
	20	c : 1	[by b:=0]
timing random 
timing: random
timing after 
timing: after
	20	a : 0
	30	b : 1	[by a:=0]
	40	c : 0	[by b:=1]
timing uniform 
timing: uniform (10)
	40	a : 1
	50	b : 0	[by a:=1]
	60	c : 1	[by b:=0]
timing uniform 
timing: uniform (30)
	60	a : 0
	90	b : 1	[by a:=0]
	120	c : 0	[by b:=1]
timing random 
timing: random
