class IO::Event::PriorityHeap

def bubble_up(index)
	parent_index = (index - 1) / 2 # watch out, integer division!
	
	while index > 0 && @contents[index] < @contents[parent_index]
		# If the node has a smaller value than its parent, swap these nodes to uphold the minheap invariant and update the index of the 'current' node. If the node is already at index 0, we can also stop because that is the root of the heap.
		# swap(index, parent_index)
		@contents[index], @contents[parent_index] = @contents[parent_index], @contents[index]
		
		index = parent_index
		parent_index = (index - 1) / 2 # watch out, integer division!
	end
end