public void dispose() {
		rowSegmentMap.clear();
		colSegmentMap.clear();
	}
Finds the column segment object for the given edge and start point.
@param edge the edge for which to find its column segment object
@param gridPoint the start point for the desired segment object
@return the column segment object for the given edge and start point.
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/layout/flowchart/EdgeSegmentMap.java