event queue:
check queue:
	time	eid	pid	event
	0	0	1	null
time: 0
event queue:
check queue:
	time	eid	pid	event
	10	1	0	
time: 0
event queue:
check queue:
	time	eid	pid	event
	20	2	0	[after=20] X?(x)
	20	3	0	X!(true)
	20	4	0	X!(false)
time: 10
event queue:
	time	eid	pid	event
	20	2	0	[after=20] X?(x)
check queue:
	20	4	0	X!(false)
	30	3	0	X!(true)
time: 20
event queue:
check queue:
	time	eid	pid	event
	20	4	0	X!(false)
	30	3	0	X!(true)
	30	2	0	[after=20] X?(x)
time: 20
ERROR: detected attempt to send on channel that is already blocked waiting to send!
	on channel[1] (X)
Run-time error while checking event.
event[3]:	30	3	0	X!(true)	[by:3]
Caught run-time exception during execution.  Halting.
... at line 19
