Binary min-heap of scheduled block ticks, ordered by due time then insertion order (stable FIFO among same-tick entries). At most one pending tick per position — re-scheduling an already-pending block is a no-op, the way fluids and redstone want it.
Schedules a tick for (x,y,z) at dueTime; ignored if one is already pending there.
dueTime
Pops and returns the earliest entry due at or before now, or undefined.
now
Binary min-heap of scheduled block ticks, ordered by due time then insertion order (stable FIFO among same-tick entries). At most one pending tick per position — re-scheduling an already-pending block is a no-op, the way fluids and redstone want it.